Perilla frutescens (L.) Britt. is a characteristic oil crop rich in polyunsaturated fatty acids, particularly α-linolenic acid, which has important development and utilization value. The Dof transcription factor is one of the plant-specific transcription factor families, which is widely involved in important biological processes such as plant growth, development, and metabolic regulation. In order to explore the key Dof transcription factors involved in the oil biosynthesis and systematically analyze their regulatory mechanisms of P. frutescens seeds, a total of 56 PfDof gene family members were identified from the genome and transcriptome data of P. frutescens and classified into four subfamilies according to sequence characteristics. All PfDofs contained highly conserved C₂-C₂ zinc finger domains, with gene duplication being the primary mechanism driving their evolution and expansion. Genes within the same subgroup exhibited similar gene structures and conserved motifs. The 56 PfDofs were predicted as unstable hydrophilic proteins, with α-helixes and random coils as their predominant structural components. The RNA-seq results revealed that 11 PfDofs exhibited differential expression during different developmental stages of P. frutescens seeds. RT-qPCR was performed to further validate the expression patterns of these 11 members across various tissue samples (root, stem, leaf, and flower) of P. frutescens and at different developmental stages of its seeds. The results showed that PfDof29 exhibited the highest expression level in seeds, which was consistent with the transcriptome data. Subcellular localization studies demonstrated that PfDof29 was localized to the nucleus and had a transcriptional activation activity. Overexpression of PfDof29 in Nicotiana tabacum resulted in a significant increase in total oil content of tobacco leaves, accompanied by reductions in starch and soluble sugar content, while the protein content remained unchanged. Additionally, the metabolic balance between saturated and unsaturated fatty acids in the transgenic tobacco leaves was altered, with a significant increase in α-linolenic acid content. The expression levels of the fatty acid desaturase genes NtFAD2, NtFAD3, and NtFAD8 were significantly upregulated. A yeast one-hybrid assay revealed that PfDof29 could directly bind to the promoter region of PfFAD8, thereby regulating its expression. This study provides an initial understanding of the regulatory mechanisms of PfDof transcription factors in the synthesis and accumulation of oil in P. frutescens. These findings offer new insights into the enhancement of oil content and quality of P. frutescens seeds.
Transcription Factors/physiology* ; Perilla frutescens/metabolism* ; Plant Proteins/metabolism* ; Gene Expression Regulation, Plant ; alpha-Linolenic Acid/biosynthesis* ; Lipids/biosynthesis* ; Seeds/genetics*

A rapid decline in egg production of laying hens begins after 480 d of age. Such a rapid decrease results predominantly from the ovarian aging, accompanied by endocrine changes, decreased yolk synthesis and accumulation, and the reduction in follicles selected into the preovulatory hierarchy. In this study, hens at 90, 150, 280, and 580 d old (D90, D150, D280, and D580, respectively) were compared for yolk precursor formation in the liver to elucidate effects of aging on laying performance. The results showed that liver lipid synthesis increased remarkably in hens from D90 to D150, but decreased sharply at D580 as indicated by the changes in triglyceride (TG) levels. This result was consistent with the age-related changes of the laying performance. The levels of liver antioxidants and total antioxidant capacity decreased significantly in D580 hens and the methane dicarboxylic aldehyde in D580 hens was much higher than that at other stages. The serum 17β-estradiol level increased from D90 to D280, but decreased at D580 (P<0.05). The expression of estrogen receptor α and β mRNAs in the liver displayed similar changes to the serum 17β-estradiol in D580 hens. Expressions of the genes related to yolk precursor formation and enzymes responsible for fat acid synthesis were all decreased in D580 hens. These results indicated that decreased yolk precursor formation in the liver of the aged hens resulted from concomitant decreases of serum 17β-estradiol level, transcription levels of estrogen receptors and critical genes involved in yolk precursor synthesis, and liver antioxidant status.
Age Factors ; Animals ; Antioxidants ; metabolism ; Chickens ; Egg Yolk ; metabolism ; Estradiol ; blood ; Female ; Lipids ; biosynthesis ; Liver ; metabolism ; Oviposition ; Receptors, Estrogen ; genetics

Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis.
Acetic Acid ; Biofuels ; Biomass ; Culture Media ; Fatty Acids ; Hydrolysis ; Industrial Microbiology ; Lignin ; chemistry ; Linoleic Acid ; Lipids ; biosynthesis ; Oleic Acid ; Rhodotorula ; metabolism

OBJECTIVETo study the effects of intrauterine growth restriction (IUGR) and high-fat diet on the growth, lipid metabolism, and related hepatic genes in rat offspring.

METHODSThe rat model of IUGR was established by food restriction during the entire pregnancy. After weaning, 32 normal rats and 24 offspring rats with IUGR were randomly allocated to standard diet group or high-fat diet group. At the age of 10 weeks, fasting plasma glucose and blood lipid were examined. Additionally, pathological sections for hepatic tissues were observed, and the transcriptional levels of related hepatic genes were measured.

RESULTSAt the age of 10 weeks, there was a significant difference in body weight between IUGR rats and normal rats on standard diets, but no significant difference in body weight was observed between the two groups on high-fat diets. Compared with the normal rats, IUGR rats showed increased energy intake and increased levels of fasting plasma glucose, total cholesterol, and triglyceride on both standard and high-fat diets. High-fat diets reduced the concentration of serum triglyceride in both normal rats and IUGR rats. IUGR and high-fat diets aggravated the fat accumulation in the liver. Two-factor analysis of variance showed that at the age of 10 weeks, the expression of genes related to lipid metabolism in the liver, PGC-1α, CPT-1, SREBF-2, HMGR, LDLR and SREBF-1, differed significantly between IUGR and normal rats. Compared with standard diets, high-fat diets increased the expression of PPARα, SREBF-1, SREBF-2, ABCG5, and CYP7A1 in both normal rats and IUGR rats. IUGR and high-fat diets had an interactive effect on LDLR expression.

CONCLUSIONSHyperlipidemia and fat accumulation in the liver observed in IUGR rats may be related to increased appetite and regulation disorder in genes related to fatty acid oxidation at the transcriptional level. High-fat diets may aggravate fat accumulation in the liver in rats, which may be related to increased expression of genes related to regulation of fatty acid synthesis at the transcriptional level and reduction in secretion of triglyceride.

Animals ; Diet, High-Fat ; Energy Intake ; Fatty Acids ; biosynthesis ; Female ; Fetal Growth Retardation ; metabolism ; Lipids ; blood ; Liver ; metabolism ; pathology ; Male ; Rats ; Rats, Sprague-Dawley ; Transcription, Genetic

Photoautotrophic cultivation with heterotrophic cells as seeds (heterotrophic cells/photoautotrophic cultivation) is an effective way for the development of microalgal biofuel, but its development potential from the point of process optimization has not been investigated in literatures. To evaluate this, the optimizations of medium and culture conditions for Chlorella ellipsoidea were studied. In the heterotrophic stage, the biomass concentration reached 11.04 g/L with the optimized medium in flask, which were 28.0% higher than that with the original medium, and the biomass concentration reached 73.89 g/L in 5-L fermenter. In the photoautotrophic stage, the culture medium and conditions were studied in a 2-L column photobioreactor. The maximum biomass concentration, lipid content and lipid productivity reached 1.62 g/L, 36.34% and 6.1 mg/(L·h) under the optimal photoautotrophic conditions. The lipids were mainly composed of C16-C18 fatty acids, which were raw material suitable for biodiesel. After optimization, heterotrophic cells/photoautotrophic cultivation can significantly improve the capacity of biofuel production by Chlorella ellipsoidea, this method is also expected to be an efficient way for the cultivation of other microalgae that can grow heterotrophically.
Biofuels ; Biomass ; Cell Culture Techniques ; Chlorella ; metabolism ; Culture Media ; Fatty Acids ; biosynthesis ; Heterotrophic Processes ; Lipids ; biosynthesis ; Photobioreactors

To evaluate the effectiveness of enzymatic assisted extraction (EAE) of lipid from the oleaginous yeast Rhodosporidium toruloides in the presence of beta-1,3-glucomannanase at a larger scale, we investigated the effects of enzymatic treatment and extraction conditions on lipid extraction yields at 10-L scale by using the broth of R. toruloides Y4 as the feed and ethyl acetate as the solvent. When it was treated for 0.5 h, the lipid extraction yield reached 71.1%, indicating that the enzymatic treatment process reached similar efficiency to that obtained at 10-mL scale. The inhibitory effect of emulsification was greatly reduced by repeated extraction. After extracted for three times, yields of lipid extraction, solvent recovery and total material recovery reached 92.9%, 87.0% and 94.2% respectively. As it can use the lipid production slurry with good extraction efficiency, EAE technology is promising for industrial production of microbial lipids.
Basidiomycota ; metabolism ; Biofuels ; Bioreactors ; Fermentation ; Industrial Microbiology ; Lipids ; biosynthesis ; isolation & purification ; beta-Mannosidase ; metabolism

Nitrogen source is one of the important factors that affect the microalgae growth and lipid accumulation. We studied the effects of various nitrogen sources (i.e. NaNO3, CO(NH2)2, NH4Cl and CH3COONH4) and amount on the growth density, lipid yield, and eicosapentaenoic acid (EPA) content of Nannochloropsis oculata by single factor experimental method. The results show that N. oculata preferred NH4+ as nitrogen source rather than NO3- and CO(NH2)2. NH4+ could promote the growth and lipid accumulation of N. oculata. With the increase of nitrogen concentration, the biomass and the content of polyunsaturated fatty acid (PUFA) increased, but the content of lipid decreased. CH3COONH4 was the most suitable for growth, accumulation of lipid and EPA of N. oculata among the four investigated nitrogen sources. The optimal concentration was 5.29 mmol/L.
Eicosapentaenoic Acid ; metabolism ; Lipids ; biosynthesis ; isolation & purification ; Microalgae ; growth & development ; metabolism ; Nitrogen ; analysis ; metabolism ; Stramenopiles ; growth & development ; metabolism

In the present study, we developed a two-liquid phase fermentation system by adding 1% n-dodecane as oxygen-vector to enhance the microbial lipids productivity of Trichosporon fermentans using cassava starch hydrolysate. Results suggest that the oxygen-vector could alleviate the oxygen shortage in flask fermentation. The cell mass and lipids concentration were 101.2 g/L and 50.28 respectively in 2 L fermenter with the presence of 1% n-dodecane. Additionally, gas chromatography analysis also reveals that the microbial lipids produced by T. fermentans contained a higher percentage of saturated fatty acid in the oxygen-vector case.
Alkanes ; chemistry ; Biofuels ; Fermentation ; Industrial Microbiology ; methods ; Lipids ; biosynthesis ; Manihot ; metabolism ; Starch ; metabolism ; Trichosporon ; genetics ; metabolism

Nannochloropsis has been considered as a promising feedstock for biodiesel production in recent years. To improve its lipid productivity, heavy-ion irradiation mutagenesis, an effectively breeding method used in plants and microorganisms was applied in Nannochloropsis oceanica OZ-1. After large-scale screening using Imaging-PAM and microplate-reader, two mutants (HP-1 and HP-2) with higher growth rate were isolated from the wild type N. oceanica. Subsequently analysis showed that after 18 days of cultivation biomass accumulation of the HP-1 and HP-2 mutant was increased by 18% and 26% respectively compare to the wild type. Total lipid productivity of the HP-1 and HP-2 mutant was 295 mg/(L x d) and 275 mg/(L x d), respectively, whereas that of the wild type was 247 mg/(L x d). Both mutants showed significantly advantage over their wild type concerning biomass accumulation and lipid productivity.
Heavy Ions ; Lipids ; biosynthesis ; Microalgae ; growth & development ; metabolism ; radiation effects ; Mutagenesis ; genetics ; Mutation ; genetics ; Stramenopiles ; genetics ; metabolism ; radiation effects

The objective of this work is to investigate how dilution rate and carbon-to-nitrogen (C/N) ratio affects lipid accumulation by Rhodosporidium toruloides AS 2.138 9 in continuous culture. Under steady-state conditions, the increase in dilution rate led to the decrease in lipid content and lipid yield. The highest lipid yield and lipid content at D = 0.02 h(-1) were 0.18 g lipid/g sugar and 57.1%, respectively, while the highest lipid productivity and biomass productivity were obtained at D = 0.14 h(-1). The increase in C/N ratio led to the increase in lipid content. The highest lipid content of 38% was obtained at C/N = 237. The highest lipid yield of 0.12 g lipid/g sugar was obtained at C/N = 92. However, the highest lipid productivity of 0.12 g/(L x h) was obtained at C/N = 32. No significant changes were observed in terms of fatty acid composition of the lipid produced under different C/N ratios, and these three fatty acids, palmitic acid, stearic acid and oleic acid, took over 85% in all samples.
Basidiomycota ; growth & development ; metabolism ; Batch Cell Culture Techniques ; Carbon ; metabolism ; Culture Media ; Fatty Acids ; metabolism ; Glucose ; metabolism ; Lipids ; biosynthesis ; Nitrogen ; metabolism ; Oleic Acid ; biosynthesis ; Palmitic Acid ; metabolism