scholarly journals Overexpression of the Transcription Factor AtLEC1 Significantly Improved the Lipid Content of Chlorella ellipsoidea

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiao Liu ◽  
Dan Zhang ◽  
Jianhui Zhang ◽  
Yuhong Chen ◽  
Xiuli Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Content ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Expression Profiles ◽  
Fatty Acid Content ◽  
Culture Conditions ◽  
Chlorella Ellipsoidea ◽  
Promising Source ◽  
Transgenic Strains

Microalgae are considered to be a highly promising source for the production of biodiesel. However, the regulatory mechanism governing lipid biosynthesis has not been fully elucidated to date, and the improvement of lipid accumulation in microalgae is essential for the effective production of biodiesel. In this study,LEAFY COTYLEDON1 (LEC1)fromArabidopsis thaliana, a transcription factor (TF) that affects lipid content, was transferred intoChlorella ellipsoidea. Compared with wild-type (WT) strains, the total fatty acid content and total lipid content ofAtLEC1transgenic strains were significantly increased by 24.20–32.65 and 22.14–29.91%, respectively, under mixotrophic culture conditions and increased by 24.4–28.87 and 21.69–30.45%, respectively, under autotrophic conditions, while the protein content of the transgenic strains was significantly decreased by 18.23–21.44 and 12.28–18.66%, respectively, under mixotrophic and autotrophic conditions. Fortunately, the lipid and protein content variation did not affect the growth rate and biomass of transgenic strains under the two culture conditions. According to the transcriptomic data, the expression of 924 genes was significantly changed in the transgenic strain (LEC1-1). Of the 924 genes, 360 were upregulated, and 564 were downregulated. Based on qRT-PCR results, the expression profiles of key genes in the lipid synthesis pathway, such asACCase,GPDH,PDAT1, andDGAT1, were significantly changed. By comparing the differentially expressed genes (DEGs) regulated byAtLEC1inC. ellipsoideaandArabidopsis, we observed that approximately 59% (95/160) of the genes related to lipid metabolism were upregulated inAtLEC1transgenicChlorella. Our research provides a means of increasing lipid content by introducing exogenous TF and presents a possible mechanism ofAtLEC1regulation of lipid accumulation inC. ellipsoidea.

scholarly journals Enhancement of Tobacco (Nicotiana tabacum L.) Seed Lipid Content for Biodiesel Production by CRISPR-Cas9-Mediated Knockout of NtAn1

2021 ◽  
Vol 11 ◽  
Author(s):  
Yinshuai Tian ◽  
Xinanbei Liu ◽  
Caixin Fan ◽  
Tingting Li ◽  
Huan Qin ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Protein Content ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
De Novo ◽  
Targeted Mutagenesis ◽  
Biodiesel Production ◽  
Seed Lipid ◽  
Tobacco Seed ◽  
Developing Seed

Tobacco (Nicotiana tabacum L.) seed lipid is a promising non-edible feedstock for biodiesel production. In order to meet the increasing demand, achieving high seed lipid content is one of the major goals in tobacco seed production. The TT8 gene and its homologs negatively regulate seed lipid accumulation in Arabidopsis and Brassica species. We speculated that manipulating the homolog genes of TT8 in tobacco could enhance the accumulation of seed lipid. In this present study, we found that the TT8 homolog genes in tobacco, NtAn1a and NtAn1b, were highly expressed in developing seed. Targeted mutagenesis of NtAn1 genes was created by the CRISPR-Cas9-based gene editing technology. Due to the defect of proanthocyanidin (PA) biosynthesis, mutant seeds showed the phenotype of a yellow seed coat. Seed lipid accumulation was enhanced by about 18 and 15% in two targeted mutant lines. Protein content was also significantly increased in mutant seeds. In addition, the seed yield-related traits were not affected by the targeted mutagenesis of NtAn1 genes. Thus, the overall lipid productivity of the NtAn1 knockout mutants was dramatically enhanced. The results in this present paper indicated that tobacco NtAn1 genes regulate both PAs and lipid accumulation in the process of seed development and that targeted mutagenesis of NtAn1 genes could generate a yellow-seeded tobacco variety with high lipid and protein content. Furthermore, the present results revealed that the CRISPR-Cas9 system could be employed in tobacco seed de novo domestication for biodiesel feedstock production.

scholarly journals Oxygen-Dependent Regulation of Bacterial Lipid Production

2015 ◽  
Vol 197 (9) ◽  
pp. 1649-1658 ◽  
Author(s):  
Kimberly C. Lemmer ◽  
Alice C. Dohnalkova ◽  
Daniel R. Noguera ◽  
Timothy J. Donohue
Keyword(s):  
Fatty Acid ◽  
Rhodobacter Sphaeroides ◽  
Lipid Content ◽  
Lipid Accumulation ◽  
Fatty Acid Content ◽  
Photosynthetic Pigment ◽  
Photosynthetic Apparatus ◽  
Content Type ◽  
Fuels And Chemicals ◽  
Insight Into

ABSTRACTUnderstanding the mechanisms of lipid accumulation in microorganisms is important for several reasons. In addition to providing insight into assembly of biological membranes, lipid accumulation has important applications in the production of renewable fuels and chemicals. The photosynthetic bacteriumRhodobacter sphaeroidesis an attractive organism to study lipid accumulation, as it has the ability to increase membrane production at low O2tensions. Under these conditions,R. sphaeroidesdevelops invaginations of the cytoplasmic membrane to increase its membrane surface area for housing of the membrane-bound components of its photosynthetic apparatus. Here we use fatty acid levels as a reporter of membrane lipid content. We show that, under low-O2and anaerobic conditions, the total fatty acid content per cell increases 3-fold. We also find that the increases in the amount of fatty acid and photosynthetic pigment per cell are correlated as O2tensions or light intensity are changed. To ask if lipid and pigment accumulation were genetically separable, we analyzed strains with mutations in known photosynthetic regulatory pathways. While a strain lacking AppA failed to induce photosynthetic pigment-protein complex accumulation, it increased fatty acid content under low-O2conditions. We also found that an intact PrrBA pathway is required for low-O2-induced fatty acid accumulation. Our findings suggest a previously unknown role ofR. sphaeroidestranscriptional regulators in increasing fatty acid and phospholipid accumulation in response to decreased O2tension.IMPORTANCELipids serve important functions in living systems, either as structural components of membranes or as a form of carbon storage. Understanding the mechanisms of lipid accumulation in microorganisms is important for providing insight into the assembly of biological membranes and additionally has important applications in the production of renewable fuels and chemicals. In this study, we investigate the ability ofRhodobacter sphaeroidesto increase membrane production at low O2tensions in order to house its photosynthetic apparatus. We demonstrate that this bacterium has a mechanism to increase lipid content in response to decreased O2tension and identify a transcription factor necessary for this response. This is significant because it identifies a transcriptional regulatory pathway that can increase microbial lipid content.

scholarly journals Suppression of E1A-Mediated Transformation by the p50E4F Transcription Factor

1999 ◽  
Vol 19 (7) ◽  
pp. 4739-4749 ◽  
Author(s):  
Elma R. Fernandes ◽  
Robert J. Rooney
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Suppressive Effect ◽  
Culture Conditions ◽  
Binding Activity ◽  
Cellular Transcription Factor ◽  
Dna Binding Activity ◽  
3T3 Fibroblasts ◽  
Induced Apoptosis ◽  
Nih 3T3

ABSTRACT The adenovirus E1A gene can act as an oncogene or a tumor suppressor, with the latter effect generally arising from the induction of apoptosis or the repression of genes that provide oncogenic growth stimuli (e.g., HER-2/c-erbB2/neu) or increased metastatic invasiveness (e.g., metalloproteases). In this study, coexpression of E1A and p50E4F, a cellular transcription factor whose DNA binding activity is stimulated by E1A, suppressed colony formation by NIH 3T3 cells and transformation of primary rat embryo fibroblasts but had no observed effect in the absence of E1A. Domains in p50E4F required for stimulation of the adenovirus E4 promoter were required for the suppressive effect, indicating a transcriptional mechanism. In serum-containing media, retroviral expression of p50E4F in E1A13S/ras-transformed NIH 3T3 fibroblasts had little effect on subconfluent cultures but accelerated a decline in viability after the cultures reached confluence. Cell death occurred by both apoptosis and necrosis, with the predominance of each process determined by culture conditions. In serum-free media, p50E4F accelerated E1A-induced apoptosis. The results suggest that p50E4F sensitizes cells to signals or conditions that cause cell death.

Comparison of biomass production and total lipid content of freshwater green microalgae cultivated under various culture conditions

2013 ◽  
Vol 37 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Geun Ho Gim ◽  
Jung Kon Kim ◽  
Hyeon Seok Kim ◽  
Mathur Nadarajan Kathiravan ◽  
Hetong Yang ◽  
...  
Keyword(s):  
Biomass Production ◽  
Total Lipid ◽  
Lipid Content ◽  
Total Lipid Content ◽  
Culture Conditions ◽  
Green Microalgae

Chicken vitellogenin gene-binding protein, a leucine zipper transcription factor that binds to an important control element in the chicken vitellogenin II promoter, is related to rat DBP

1991 ◽  
Vol 11 (10) ◽  
pp. 4863-4875
Author(s):  
S V Iyer ◽  
D L Davis ◽  
S N Seal ◽  
J B Burch
Keyword(s):  
Transcription Factor ◽  
Binding Site ◽  
Binding Protein ◽  
Expression Profiles ◽  
Control Element ◽  
Cdna Expression Library ◽  
Leucine Zippers ◽  
Expression Library ◽  
Positive Elements ◽  
Vitellogenin Gene

We screened a chicken liver cDNA expression library with a probe spanning the distal region of the chicken vitellogenin II (VTGII) gene promoter and isolated clones for a transcription factor that we have named VBP (for vitellogenin gene-binding protein). VBP binds to one of the most important positive elements in the VTGII promoter and appears to play a pivotal role in the estrogen-dependent regulation of this gene. The protein sequence of VBP was deduced from a nearly full length cDNA copy and was found to contain a basic/zipper (bZIP) motif. As expected for a bZIP factor, VBP binds to its target DNA site as a dimer. Moreover, VBP is a stable dimer free in solution. A data base search revealed that VBP is related to rat DBP. However, despite the fact that the basic/hinge regions of VBP and DBP differ at only three amino acid positions, the DBP binding site in the rat albumin promoter is a relatively poor binding site for VBP. Thus, the optimal binding sites for VBP and DBP may be distinct. Similarities between the VBP and DBP leucine zippers are largely confined to only four of the seven helical spokes. Nevertheless, these leucine zippers are functionally compatible and appear to define a novel subfamily. In contrast to the bZIP regions, other portions of VBP and DBP are markedly different, as are the expression profiles for these two genes. In particular, expression of the VBP gene commences early in liver ontogeny and is not subject to circadian control.

Proximate composition of male and female African catfish (Clarias gariepinus) and tilapia (Tilapia zilli) in Jega river, Kebbi state, Nigeria

2020 ◽  
Vol 01 (02) ◽  
pp. 28-35
Author(s):  
W. M. Namaga ◽  
B. Yahaya ◽  
M. A. Salam
Keyword(s):  
Protein Content ◽  
Fish Species ◽  
Lipid Content ◽  
Proximate Composition ◽  
Clarias Gariepinus ◽  
Fibre Content ◽  
African Catfish ◽  
Male And Female ◽  
Juvenile Female ◽  
Significant Difference

Fish is highly nutritious, tasty, and easily digestible. It is much sought after by a broad cross-section of the world’s population, particularly in developing countries as it provides the cheapest protein source. Nigeria is blessed with numerous inland freshwater rivers and lakes scattered all over the country. This freshwater habitat consists of many species of fish that have successfully dominated all niches over time and have for many reasons remained unstudied. The situation concealed a lot of scientific information particularly on food security and safety to the inmates and the country at large. Jega River which transcended many States in the North-Western part of Nigeria to open into the river Niger is one of such rivers largely uncared for, study-wise. African catfish (Clarias gariepinus) and Tilapia (Tilapia zillii) have been wisely selected for the present proximate composition studies. The juveniles of these fishes were purchased from local fishermen in Mariner Waje landing site of the river which flows by Jega town, a local government area in Kebbi State, Nigeria. For the study, the methodology approved by the Association of Official Analytical Chemists (AOAC) was used to determine the proximate composition of the fishes. The highest percentage crude protein content of 49.18 ± 0.30% was observed in juvenile female C. gariepinus; while the lowest protein content of 39.22± 0.50% was observed in juvenile male T. zilli. The highest percentage lipid content of 11.75± 1.50% was observed in juvenile female tilapia; while the lowest percentage lipid content of 6.25± 0.29% was observed in male African catfish. The highest percentage fibre content of 4.00 ± 0.29% was observed in male and female C. gariepinus, while the lowest percentage fibre content of 0.75± 0.29% was observed in male tilapia. There were variations (p< 0.05) when the protein and lipid contents of both the species were compared with each other. There was also a significant difference (p< 0.05) when the carbohydrate contents were compared between the fish species, but there was no significant difference (p > 0.05) when the fibre content was compared within the species. The analyses showed that both the male and female fish species studied had high protein contents.

scholarly journals Streptomyces: isolation, optimization of culture conditions and extraction of secondary metabolites

2016 ◽  
Vol 5 (3) ◽  
pp. 27-32 ◽  
Author(s):  
Ahmed I. Khattab ◽  
Eltahir H. Babiker ◽  
Humodi A. Saeed
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Pharmaceutical Journal ◽  
Growth Conditions ◽  
Culture Conditions ◽  
Physical Culture ◽  
Indicator Organisms ◽  
Streptomyces Spp ◽  
Promising Source ◽  
Soil Sediments

The objectives of this study were to isolate and identify Streptomyces from soil sediments as well as to optimize cultural growth conditions for maximum antibacterial productivity. A total of fifty soil sediments were collected from Red Sea, Sudan. The soil sediments were pretreated and cultivated on agar medium. Promising Streptomyces spp. were isolated by agar overlay method using indicator organisms. Optimization of chemical and physical culture conditions was carried out. The later was judged by assessment of antibacterial activity. Ethyl acetate was used to extract the secondary metabolite compounds. The separation of the active ingredients was performed using both thin layer chromatography (TLC) and gas chromatography-mass spectrometer (GC-MS). The results revealed nine strains of Streptomyces. Of them two (PS1 and PS28) isolates exhibited high activity against pathogenic bacteria. The optimum growth conditions were pH 7.5, temperature at 30°C, soyabean concentration 2.5 g/l, incubation period in 7 days, MgSO4.7H2O conc. 1g/l and K2HPO4 conc. 2.5g/l. TLC test showed three and two fragments from metabolites of PS1 and PS28 respectively, while the GC-MS analysis revealed eight and eleven compounds with antibacterial activity of PS1 and PS28 respectively. It is concluded that marine is promising source of secondary metabolites.Khattab et al., International Current Pharmaceutical Journal, February 2016, 5(3): 27-32

Sign in / Sign up

Export Citation Format

Share Document