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Peanut (Arachis hypogaea L.) is one of the important oil crops worldwide. Revealing the molecular basis of seed oil synthesis and analyzing key candidate genes may have important implications for enhancing peanut production. In this study, we investigated the dynamic changes in the oil accumulation rate and gene expression levels in developing peanut seeds. A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that the up-regulated differentially expressed genes (DEGs) among three varieties at 25–35 days after flowering (DAF) were involved in fatty acid synthesis, carbon metabolism, and pyruvate metabolism. Between 25 and 35 DAF, the up-regulated DEGs in the high-oil varieties, but not in the low-oil variety, were related to acetyl-CoA synthesis. We examined the differences in the varieties at the same stages. We analyzed the lipid metabolism-related genes by protein–protein interaction (PPI), and finally identified 57 DEGs that may influence the peanut oil content. These candidate genes included three genes encoding acetyl-CoA carboxylase (ACCase), one gene encoding ketoacyl-ACP synthase III (KASIII), one gene encoding hydroxyacyl-ACP dehydrase (HAD), and one gene encoding enoyl-ACP reductase (EAR), which form the Type II fatty acid synthase complex. Additionally, we also found that 11 transcription factors may affect oil content. These identified candidate genes may help to further clarify the molecular basis of the oil accumulation in peanut seeds. [ABSTRACT FROM AUTHOR]

At present, antimicrobial resistance is one of the most significant public health challenges [...]

‘Diacylglycerol acyltransferase (DGAT)’ acts as a key rate-limiting enzyme that catalyzes the final step of the de novo biosynthesis of triacylglycerol (TAG). The study was to characterize the function of the DGAT3 gene in Paeonia rockii, which is known for its accumulation of high levels of unsaturated fatty acids (UFAs). We identified a DGAT3 gene which encodes a soluble protein that is located within the chloroplasts of P. rockii. Functional complementarity experiments in yeast demonstrated that PrDGAT3 restored TAG synthesis. Linoleic acid (LA, C18:2) and α-linolenic acid (ALA, C18:3) are essential unsaturated fatty acids that cannot be synthesized by the human body. Through the yeast lipotoxicity test, we found that the yeast cell density was largely increased by adding exogenous LA and, especially, ALA to the yeast medium. Further ectopic transient overexpression in Nicotiana benthamiana leaf tissue and stable overexpression in Arabidopsis thaliana indicated that PrDGAT3 significantly enhanced the accumulation of the TAG and UFAs. In contrast, we observed a significant decrease in the total fatty acid content and in several major fatty acids in PrDGAT3-silenced tree peony leaves. Overall, PrDGAT3 is important in catalyzing TAG synthesis, with a substrate preference for UFAs, especially LA and ALA. These results suggest that PrDGAT3 may have practical applications in improving plant lipid nutrition and increasing oil production in plants.

In this study, the effect of rutin on fatty acid metabolism and antioxidant activity were evaluated. We found that the antioxidant capacity of rutin‐treated Caenorhabditis elegans was enhanced but the triglyceride content was significantly reduced. The reduction of fat accumulation by rutin was also confirmed by Oil Red O staining. RNA‐seq analysis indicated that rutin significantly regulated the expression of seven genes related to lipid metabolism in C. elegans. Among the seven genes, acox‐1.3, stdh‐3, and fat‐7 were associated with fatty acid metabolism. Rutin significantly reduced fat accumulation in both fat‐6 and fat‐7 mutant strains but did not affect the fat storage of fat‐6/fat‐7 double mutant, which indicated that the impact of rutin on fat storage depended on fat‐6 and fat‐7. These findings indicated that rutin reduced fat storage depending on the regulation of lipid metabolism‐related genes expression and thereby regulating the biosynthesis of the corresponding unsaturated fatty acid. [ABSTRACT FROM AUTHOR]

To combat the rise in antibiotic resistance, new targets must be identified and probes against them developed. Protein‐protein interactions (PPI) of bacterial type II fatty acid biosynthesis (FAS‐II) represent an untapped, yet rich area for new antibiotic discovery. Here, we present a computational and in vitro workflow for the discovery of new inhibitors of PPI in Escherichia coli FAS‐II. As part of this study, we identified suramin, an existing treatment for African sleeping sickness, to effectively block the interaction of E. coli dehydratase FabA and the acyl carrier protein EcACP, with an IC50 = 85 μΜ. This finding validates a workflow that combines in silico screening with in vitro PPI assays to identify probes appropriate for further optimization. [ABSTRACT FROM AUTHOR]

Summary: To enrich our knowledge about gene network of fatty acid biosynthesis in cottonseed, we conducted comparative transcriptome to reveal the differences in gene expression between Gossypium hirsutum and Gossypium barbadense during cottonseed development. The prolonged expression period and increased expression abundance of oil‐related genes are the main reasons for producing high seed oil content (SOC) in G. barbadense, which manifested as the bias of homeologous gene expression in Dt‐subgenome after 25 day postanthesis (DPA). The dynamic expression profile showed that SAD6 and FATA are more important for oil biosynthesis in G. barbadense than that in G. hirsutum. Three key transcription factors, WRI1, NF‐YB6 and DPBF2, showed their elite roles in regulating seed oil in cotton. We observed that sequence variations in the promoter region of BCCP2 genes might contribute to its divergence in expression level between the two species. Based on the quantitative trait loci (QTL) information of the seed oil content and utilizing additional G. barbadense introgression lines (ILs), we propose 21 candidate genes on the basis of their differential expression level, of which the GbSWEET and the GbACBP6 showed the potential functional to improve the oil content. Taken together, studying the different expression of oil‐related genes and their genetic regulation mechanisms between G. hirsutum and G. barbadense provide new insights to understanding the mechanism of fatty acid biosynthesis network and fatty acid genetic improving breeding in cotton. [ABSTRACT FROM AUTHOR]

Comparative studies of proteome analysis, photosynthetic activity and fatty acid biosynthesis of the glnA - and glsF -overexpressing strains and the wild-type (WT) were carried out to elucidate the possible role(s) of the two enzymes, glutamine synthetase (GS) and glutamate synthase (GOGAT) in the GS-GOGAT cycle under nitrogen starvation. The evidence indicated the role of GS and GOGAT in the regulatory mechanism of carbon (C-) and nitrogen (N-) assimilation and the induction of photosynthesis and lipid/fatty acid biosynthesis pathway under N-stress. The fatty acid profile of the GS-overexpressing strain (WT + GlnA) under the stress showed a drastic increase in the levels of C18:1Δ9 and C18:1Δ11, whereas only C18:1Δ9 was significantly induced in the GOGAT-overexpressing strain (WT + GlsF). Moreover, the proteome analysis and oxygen evolution data showed that the extra-GS activity in the mutant (MT) cells led to the increasing of proteins involved in photosynthesis as well as the rate of oxygen evolution in the first 24 h after nitrogen depletion, suggesting its role in promoting conversion of light energy to chemical energy under the stress. • GS-GOGAT cycle could enhance photosynthesis in the absence of nitrogen supply. • GOGAT promoted photosynthesis under N-stress by maintaining the Δ-O 2 evolution rate. • GOGAT overexpressing cells showed accumulation of C18:1Δ11 under N-starvation. • C18:1Δ9 and C18:1Δ11 compositions increased in GS overexpressing cells under N-stress. • Fatty acid accumulation was affected by overexpressing GS and GOGAT under N-stress. [ABSTRACT FROM AUTHOR]

Biosynthesis and storage of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is under dietary and genetic control in Atlantic salmon (Salmo salar). Enhanced EPA and DHA biosynthesis and storage may improve utilization, and thus reduce marine forage fish oil use in aquafeeds. To determine phenotypic variability in EPA and DHA tissue content and growth performance, 50 families (n = 30 salmon/family, 48 g/fish initial weight) of Atlantic salmon (Saint John River strain) were reared in freshwater and fed either a fish oil (FO) control diet or FO-free diet. After 16 weeks, body size was recorded. Salmon fed the FO-free diet overall showed significantly lower growth performance compared to salmon fed the FO control diet, regardless of family. To determine the relationship between growth and FA content, the five families with the highest and the five families with the lowest weight gain were sampled for tissue and liver FA analysis. There was a significant interaction between growth and diet. The family x diet interaction was significant for final weight, final length, weight gain, growth rate and feed conversion ratio. Among the five fastest growing families, there was a significant family effect for EPA and DHA storage in the liver but not for muscle. Among the five slowest growing families, by comparison salmon had similar liver DHA and EPA content, independent of diet treatment. Family and diet were interacting factors that determine EPA and DHA storage in liver. Certain fast-growing families also had significantly higher DHA content in liver and muscle. This study demonstrates the potential for selecting families that can better utilize a diet without marine forage fish oil. • Growth among 50 families of salmon was dependent on family x diet interaction. • EPA+ DHA storage was more influenced by family in liver than muscle. • Family and diet were interacting factors that determined EPA+ DHA storage in liver. • Specific fast-growing families were identified that had higher DHA storage. • There is potential for selecting families that better utilize a fish oil-free diet. [ABSTRACT FROM AUTHOR]

Introduction: With regard to the anti-mycobacterial activity of 2-pyrazinoic acid esters (POEs), recent studies have shown that both pyrazine core and alkyl part of POE interact with the fatty acid synthase type (I) (FAS (I)) precluding a complex formation between NADPH and FAS (I). Methods: Considering this interaction at the reductase site of FAS (I) responsible for reduction of β-ketoacyl-CoA to β-hydroxyacyl-CoA, we hypothesized that POE containing a bioreducible center in its alkyl part might show an increased anti-tubercular activity due to the involvement of FAS (I) in extra bio-reduction reaction. Thus, we synthesized novel POEs, confirmed their structures by spectral data, and subsequently evaluated their anti-mycobacterial activity against Mycobacterium tuberculosis (Mtb) (H37Rv) strain at 10 μg/mL concentration. Results: Compounds 3c, 3j, and 3m showed higher activity with regard to the inhibition of Mtb growth by 45.4, 45.7, and 51.2% respectively. Unexpectedly, the maltol derived POE 3l having the lowest log p value among the POEs indicated the highest anti-mycobacterial growth activity with 56% prevention. Compounds 3c and 3l showed no remarkable cytotoxicity on human macrophages at 10 μg/mL concentration as analyzed by xCELLigence real-time cell analysis. In further experiments, some of the tested POEs, unlike pyrazinamide (PZA), exhibited significant antibacterial and also anti-fungal activities. POEs showed an enhanced bactericidal activity on gram-positive bacteria as shown for Staphylococcus aureus, e.g. compound 3b with a MIC value of 125 μg/mL but not E. coli as a gram-negative bacteria, except for maltol derived POE (3l) that showed an inverse activity in the susceptibility test. In the anticancer activity test against the human leukemia K562 cell lines using MTT assay, compounds 3e and 3j showed the highest cytotoxic effect with IC50 values of 25±8.0 μΜ and 25±5.0 μΜ, respectively. Conclusion: It was found that the majority of POEs containing a bioreducible center showed higher inhibitory activities on Mtb growth when compared to the similar compounds without a bio-reducible functional group.

Abstract Background Sustainable production of microbial fatty acids derivatives has the potential to replace petroleum based equivalents in the chemical, cosmetic and pharmaceutical industry. Most fatty acid sources for production oleochemicals are currently plant derived. However, utilization of these crops are associated with land use change and food competition. Microbial oils could be an alternative source of fatty acids, which circumvents the issue with agricultural competition. Results In this study, we generated a chimeric microbial production system that features aspects of both prokaryotic and eukaryotic fatty acid biosynthetic pathways targeted towards the generation of long chain fatty acids. We redirected the type-II fatty acid biosynthetic pathway of Escherichia coli BL21 (DE3) strain by incorporating two homologues of the beta-ketoacyl-[acyl carrier protein] synthase I and II from the chloroplastic fatty acid biosynthetic pathway of Arabidopsis thaliana. The microbial clones harboring the heterologous pathway yielded 292 mg/g and 220 mg/g DCW for KAS I and KAS II harboring plasmids respectively. Surprisingly, beta-ketoacyl synthases KASI/II isolated from A. thaliana showed compatibility with the FAB pathway in E. coli. Conclusion The efficiency of the heterologous plant enzymes supersedes the overexpression of the native enzyme in the E. coli production system, which leads to cell death in fabF overexpression and fabB deletion mutants. The utilization of our plasmid based system would allow generation of plant like fatty acids in E. coli and their subsequent chemical or enzymatic conversion to high end oleochemical products.

Abstract Background Sea buckthorn is a woody oil crop in which palmitoleic acid (C16:1n7, an omega-7 fatty acid (FA)) contributes approximately 40% of the total FA content in berry pulp (non-seed tissue). However, the molecular mechanisms contributing to the high accumulation of C16:1n7 in developing sea buckthorn berry pulp (SBP) remain poorly understood. Results We identified 1737 unigenes associated with lipid metabolism through RNA-sequencing analysis of the four developmental stages of berry pulp in two sea buckthorn lines, ‘Za56’ and ‘TF2–36’; 139 differentially expressed genes were detected between the different berry pulp developmental stages in the two lines. Analyses of the FA composition showed that the C16:1n7 contents were significantly higher in line ‘Za56’ than in line ‘TF2–36’ in the mid-late developmental stages of SBP. Additionally, qRT-PCR analyses of 15 genes involved in FA and triacylglycerol (TAG) biosynthesis in both lines revealed that delta9-ACP-desaturase (ACP-Δ9D) competed with 3-ketoacyl-ACP-synthase II (KASII) for the substrate C16:0-ACP and that ACP-Δ9D and delta9-CoA-desaturase (CoA-Δ9D) gene expression positively correlated with C16:1n7 content; KASII and fatty acid elongation 1 (FAE1) gene expression positively correlated with C18:0 content in developing SBP. Specifically, the abundance of ACP-Δ9D and CoA-Δ9D transcripts in line ‘Za56’, which had a higher C16:1n7 content than line ‘TF2–36’, suggests that these two genes play an important role in C16:1n7 biosynthesis. Furthermore, the high expressions of the glycerol-3-phosphate dehydrogenase (GPD1) gene and the WRINKLED1 (WRI1) transcription factor contributed to increased biosynthesis of TAG precursor and FAs, respectively, in the early developmental stages of SBP, and the high expression of the diacylglycerol O-acyltransferase 1 (DGAT1) gene increased TAG assembly in the later developmental stages of SBP. Overall, we concluded that increased ACP-Δ9D and CoA-Δ9D levels coupled with decreased KASII and FAE1 activity is a critical event for high C16:1n7 accumulation and that the coordinated high expression of WRI1, GPD1, and DGAT1 genes resulted in high oil accumulation in SBP. Conclusion Our results provide a scientific basis for understanding the mechanism of high C16:1n7 accumulation in berry pulp (non-seed tissue) and are valuable to the genetic breeding programme for achieving a high quality and yield of SBP oil.

Abstract Background Lactones are highly valuable cyclic esters of hydroxy fatty acids that find application as pure fragrances or as building blocks of speciality chemicals. While chemical synthesis often leads to undesired racemic mixtures, microbial production allows obtaining optically pure lactones. The production of a specific lactone by biotransformation depends on the supply of the corresponding hydroxy fatty acid, which has economic and industrial value similar to γ-lactones. Hence, the identification and exploration of microorganisms with the rare natural ability for de novo biosynthesis of lactones will contribute to the long-term sustainability of microbial production. In this study, the innate ability of Ashbya gossypii for de novo production of γ-lactones from glucose was evaluated and improved. Results Characterization of the volatile organic compounds produced by nine strains of this industrial filamentous fungus in glucose-based medium revealed the noteworthy presence of seven chemically different γ-lactones. To decipher and understand the de novo biosynthesis of γ-lactones from glucose, we developed metabolic engineering strategies focused on the fatty acid biosynthesis and the β-oxidation pathways. Overexpression of AgDES589, encoding a desaturase for the conversion of oleic acid (C18:1) into linoleic acid (C18:2), and deletion of AgELO624, which encodes an elongase that catalyses the formation of C20:0 and C22:0 fatty acids, greatly increased the production of γ-lactones (up to 6.4-fold; (7.6 ± 0.8) × 103 µg/gCell Dry Weight). Further substitution of AgPOX1, encoding the exclusive acyl-CoA oxidase in A. gossypii, by a codon-optimized POX2 gene from Yarrowia lipolytica, which encodes a specific long chain acyl-CoA oxidase, fine-tuned the biosynthesis of γ-decalactone to a relative production of more than 99%. Conclusions This study demonstrates the potential of A. gossypii as a model and future platform for de novo biosynthesis of γ-lactones. By means of metabolic engineering, key enzymatic steps involved in their production were elucidated. Moreover, the combinatorial metabolic engineering strategies developed resulted in improved de novo biosynthesis of γ-decalactone. In sum, these proof-of-concept data revealed yet unknown metabolic and genetic determinants important for the future exploration of the de novo production of γ-lactones as an alternative to biotransformation processes.

Akebia trifoliata (Thunb.) Koidz is an important Chinese medicinal and economic crop. Its seeds, which are rich in fatty acids, are usually discarded. As of now, A. trifoliata lipid biosynthesis pathways and genes have not been clearly described. In this work, we found that seed and fruit development of A. trifoliata were not synchronized, and that when the fruit was ripe, seed oil content was not at its highest. As seeds developed, linoleic and oleic acid content was found to decrease and increase, respectively. RNA sequencing yielded 108.45 GB of clean reads from 15 cDNA libraries, containing 8756 differentially expressed genes. We identified 65 unigenes associated with lipid biosynthesis, including fatty acid and triacylglycerol biosynthesis. The 65 unigenes were mapped to the A. trifoliata lipid synthesis pathway. There were 20 AtrFAD family members in A. trifoliata, which could be divided into four sub-groups with the highest number of AtrSADs. Our study revealed the dynamic changes in A. trifoliata seed oil content and composition during its growth period and provides large-scale and comprehensive transcriptome data of A. trifoliata seeds. These findings provide a basis for the improvement of A. trifoliata seed oil yield and quality.

Abstract Background The catabolite control protein A (CcpA) is a master regulator of many important cellular processes in Gram-positive bacteria. In Lactobacillus plantarum, CcpA directly or indirectly controls the transcription of a large number of genes that are involved in carbohydrate metabolism, aerobic and anaerobic growth, stress response and metabolite production, but its role in response to different carbon sources remains unclear. Results Here a combined transcriptomic and physiological approach was used to survey the global alterations that occurred during the logarithmic growth phase of wild-type and ccpA mutant strains of L. plantarum ST-III using fructooligosaccharides (FOS) or glucose as the sole carbon source. The inactivation of ccpA significantly affected the growth and production of metabolites under both carbon sources. About 15% of the total genes were significantly altered between wild-type and ccpA strains grown on glucose and the value is deceased to 12% when these two strains were compared on FOS, while only 7% were obviously changed due to the loss of CcpA when comparing strains grown on glucose and FOS. Although most of the differentially expressed genes mediated by CcpA are glucose dependent, FOS can also induce carbon catabolite repression (CCR) through the CcpA pathway. Moreover, the inactivation of ccpA led to a transformation from homolactic fermentation to mixed fermentation under aerobic conditions. CcpA can control genes directly by binding in the regulatory region of the target genes (mixed fermentation), indirectly through local regulators (fatty acid biosynthesis), or have a double effect via direct and indirect regulation (FOS metabolism). Conclusion Overall, our results show that CcpA plays a central role in response to carbon source and availability of L. plantarum and provide new insights into the complex and extended regulatory network of lactic acid bacteria.

Background: The unicellular alga Haematococcus pluvialis has achieved considerable interests for its capacity to accumulate large amounts of triacylglycerol and astaxanthin under various environmental stresses. To our knowledge, studies focusing on transcriptome research of H. pluvialis under exogenous hormones together with physical stresses are rare. In the present study, the change patterns at transcriptome level were analyzed to distinguish the multiple defensive systems of astaxanthin and fatty acid metabolism against exogenous salicylic acid and high light (SAHL) stresses. Results: Based on RNA-seq data, a total of 112,463 unigenes and 61,191 genes were annotated in six databases, including NR, KEGG, Swiss-Prot, PFAM, COG and GO. Analysis of differentially expressed genes (DEGs) in KEGG identified many transcripts that associated with the biosynthesis of primary and secondary metabolites, photosynthesis, and immune system responses. Furthermore, 705 unigenes predicted as putative transcription factors (TFs) were identified, and the most abundant TFs families were likely to be associated with the biosynthesis of astaxanthin and fatty acid in H. pluvialis upon exposure to SAHL stresses. Additionally, majority of the fifteen key genes involved in astaxanthin and fatty acid biosynthesis pathways presented the same expression pattern, resulting in increased accumulation of astaxanthin and fatty acids in single celled H. pluvialis, in which astaxanthin content increased from 0.56 ± 0.05 mg·L−1 at stage Control to 0.89 ± 0.12 mg·L−1 at stage SAHL_48. And positive correlations were observed among these studied genes by Pearson Correlation (PC) analysis, indicating the coordination between astaxanthin and fatty acid biosynthesis. In addition, protein–protein interaction (PPI) network analysis also demonstrated that this coordination might be at transcriptional level. Conclusion: The results in this study provided valuable information to illustrate the molecular mechanisms of coordinate relations between astaxanthin and fatty acid biosynthesis. And salicylic acid might play a role in self-protection processes of cells, helping adaption of H. pluvialis to high light stress. [ABSTRACT FROM AUTHOR]

Large‐scale copepod production is limited by high‐complexity production of microalgae with high contents of polyunsaturated fatty acids (PUFA). However, the tropical A. royi and P. annandalei show great promise of being cultivable on diets with less PUFA content while maintaining both population density and adequate fatty acid (FA) profiles. This ability was investigated through analysis of population density, development stage composition and FA compositions when fed diets of varying FA profiles: the microalgae Dunaliella tertiolecta and Rhodomonas salina, and baker's yeast, Saccharomyces cerevisiae. For A. royi, the population density (>1,600 L−1) did not differ significantly when fed these food items, nor did the relative content of the essential FA, docosahexaenoic acid (C22:6n‐3, DHA), >28% of total FA (p <.05). P. annandalei did not reproduce when fed S. cerevisiae, but population density (>300 L−1) and DHA content (30%–60% DHA of total FA) did not differ significantly when fed D. tertiolecta and R. salina (p <.05). Eicosapentaenoic acid (C20:5n‐3, EPA) content of both copepods differed dependent on the diet, but the resulting DHA:EPA ratio were >2, the optimal for live feed for fish larvae. These findings demonstrate possibilities of utilizing A. royi and P. annandalei in intensive aquaculture, exploiting cheaper diet alternatives, and possibly reducing total production cost and complexity. [ABSTRACT FROM AUTHOR]

Perilla, also termed as purple mint, Chinese basil, or Perilla mint, is a flavoring herb widely used in East Asia. Both crude oil and essential oil are employed for consumption as well as industrial purposes. Fatty acids (FAs) biosynthesis and oil body assemblies in Perilla have been extensively investigated over the last three decades. Recent advances have been made in order to reveal the enzymes involved in the fatty acid biosynthesis in Perilla. Among those fatty acids, alpha-linolenic acid retained the attention of scientists mainly due to its medicinal and nutraceutical properties. Lipids synthesis in Perilla exhibited similarities with Arabidopsis thaliana lipids’ pathway. The homologous coding genes for polyunsaturated fatty acid desaturases, transcription factors, and major acyl-related enzymes have been found in Perilla via de novo transcriptome profiling, genome-wide association study, and in silico whole-genome screening. The identified genes covered de novo fatty acid synthesis, acyl-CoA dependent Kennedy pathway, acyl-CoA independent pathway, Triacylglycerols (TAGs) assembly, and acyl editing of phosphatidylcholine. In addition to the enzymes, transcription factors including WRINKLED, FUSCA3, LEAFY COTYLEDON1, and ABSCISIC ACID INSENSITIVE3 have been suggested. Meanwhile, the epigenome aspect impacting the transcriptional regulation of FAs is still unclear and might require more attention from the scientific community. This review mainly outlines the identification of the key gene master players involved in Perilla FAs biosynthesis and TAGs assembly that have been identified in recent years. With the recent advances in genomics resources regarding this orphan crop, we provided an updated overview of the recent contributions into the comprehension of the genetic background of fatty acid biosynthesis. The provided resources can be useful for further usage in oil-bioengineering and the design of alpha-linolenic acid-boosted Perilla genotypes in the future.

Sunflower is an important oilseed crop in which the biochemical pathways leading to seed oil synthesis and accumulation have been widely studied. However, how these pathways are regulated is less well understood. The WRINKLED1 (WRI1) transcription factor is considered a key regulator in the control of triacylglycerol biosynthesis, acting through the AW box binding element (CNTNG(N)7CG). Here, we identified the sunflower WRI1 gene and characterized its activity in electrophoretic mobility shift assays. We studied its role as a co-regulator of sunflower genes involved in plastidial fatty acid synthesis. Sunflower WRI1-targets included genes encoding the pyruvate dehydrogenase complex, the α-CT and BCCP genes, genes encoding ACPs and the fatty acid synthase complex, together with the FATA1 gene. As such, sunflower WRI1 regulates genes involved in seed plastidial fatty acid biosynthesis in a coordinated manner, establishing a WRI1 push and pull strategy that drives oleic acid synthesis for its export into the cytosol. We also determined the base bias at the N positions in the active sunflower AW box motif. The sunflower AW box is sequence-sensitive at the non-conserved positions, enabling WRI1-binding. Moreover, sunflower WRI1 could bind to a non-canonical AW-box motif, opening the possibility of searching for new target genes.

Background: Paeonia lactiflora 'Hangshao' is widely cultivated in China as a traditional Chinese medicine 'Radix Paeoniae Alba'. Due to the abundant unsaturated fatty acids in its seed, it can also be regarded as a new oilseed plant. However, the process of the biosynthesis of unsaturated fatty acids in it has remained unknown. Therefore, transcriptome analysis is helpful to better understand the underlying molecular mechanisms. Results: Five main fatty acids were detected, including stearic acid, palmitic acid, oleic acid, linoleic acid and α-linolenic acid, and their absolute contents first increased and then decreased during seed development. A total of 150,156 unigenes were obtained by transcriptome sequencing. There were 15,005 unigenes annotated in the seven functional databases, including NR, NT, GO, KOG, KEGG, Swiss-Prot and InterPro. Based on the KEGG database, 1766 unigenes were annotated in the lipid metabolism. There were 4635, 12,304, and 18,291 DEGs in Group I (60 vs 30 DAF), Group II (90 vs 60 DAF) and Group III (90 vs 30 DAF), respectively. A total of 1480 DEGs were detected in the intersection of the three groups. In 14 KEGG pathways of lipid metabolism, 503 DEGs were found, belonging to 111 enzymes. We screened out 123 DEGs involved in fatty acid biosynthesis (39 DEGs), fatty acid elongation (33 DEGs), biosynthesis of unsaturated fatty acid (24 DEGs), TAG assembly (17 DEGs) and lipid storage (10 DEGs). Furthermore, qRT-PCR was used to analyze the expression patterns of 16 genes, including BBCP, BC, MCAT, KASIII, KASII, FATA, FATB, KCR, SAD, FAD2, FAD3, FAD7, GPAT, DGAT, OLE and CLO, most of which showed the highest expression at 45 DAF, except for DGAT, OLE and CLO, which showed the highest expression at 75 DAF. Conclusions: We predicted that MCAT, KASIII, FATA, SAD, FAD2, FAD3, DGAT and OLE were the key genes in the unsaturated fatty acid biosynthesis and oil accumulation in herbaceous peony seed. This study provides the first comprehensive genomic resources characterizing herbaceous peony seed gene expression at the transcriptional level. These data lay the foundation for elucidating the molecular mechanisms of fatty acid biosynthesis and oil accumulation for herbaceous peony. [ABSTRACT FROM AUTHOR]

The present study searched for candidate genes in five linkage groups (LGs) - T2, T3, OT4, OT6 and T9 hosting the QTLs associated with iodine value (IV) and fatty acid composition (FAC) in an oil palm interspecific hybrid population. Each of the five LGs was successfully anchored to its corresponding chromosomal segment where, a wider repertoire of candidate genes was identified. This study further revealed a total of 19 candidate genes and four transcription factors involved in biosynthesis of fatty acids, lipids (including triacylglycerol) and acetyl-CoA, glycosylation and degradation of fatty acids. Their possible involvement in regulating the levels of saturation are discussed. In addition, 22 candidate genes located outside the QTL intervals were also identified across the interspecific hybrid genome. A total of 92 SSR markers were developed to tag the presence of these candidate genes and 50 were successfully mapped onto their respective positions on the genome. The data obtained here complements the previous studies, and collectively, these QTL-linked candidate gene markers could help breeders in more precisely selecting palms with the desired FAC. [ABSTRACT FROM AUTHOR]

Ampicillin sodium salt (AMP) is commonly and effectively used to prevent bacterial infection in algal culture, but the response of algal strains to AMP has not been investigated. In this study, Chlorella sorokiniana was selected to evaluate the influence of AMP on algae. AMP enhanced the contents of chlorophyll and two fatty acids, myristic acid (C22:1N9) and tetracosanoic acid (C6:0), but inhibited the growth, carotenoid production, and contents of 16 fatty acids in C. sorokiniana. A global transcriptome analysis from experimental data identified 3 825 upregulated and 1 432 downregulated differentially expressed genes (DEGs) in C. sorokiniana. The upregulated DEGs, such as hemB/alaD, mmaB/pduO, cox15/ctaA, fxN, cpoX/hemF, and earS/gltX, were enriched in the porphyrin and chlorophyll metabolism pathways, whereas the downregulated DEGs, including lcyB (crtL1), crtY (lcyE, crtL2), lut1 (CYP97C1), z-isO, crtZ and crtisO (crtH), were enriched in the carotenoid biosynthesis pathway, and the downregulated DEGs, abH, fadD, fabF, acsL, fabG, and accD were enriched in the fatty acid biosynthesis pathway. Thus, the use of AMP to obtain an axenic strain revealed that AMP might affect the regulatory dynamics and the results of the metabolic process in C. sorokiniana. The data obtained in the study provide foundational information for algal purification and aseptic processing. [ABSTRACT FROM AUTHOR]

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Background: AMP-activated protein kinase (AMPK) is an important regulator for lipid accumulation, potentially known to have an inhibitory role in lipid synthesis. It inactivates acetyl-CoA carboxylase (ACC), an important regulatory enzyme required for lipid synthesis. However, in Mucor circinelloides, AMPK and its association with lipid accumulation has not been studied yet. Objectives: To identify AMPK genes in M. circinelloides and to compare their expression levels in high and low lipid-producing strains of M. circinelloides to predict the possible roles of AMPK in lipid metabolism and to select candidate genes for further studies to enhance lipid accumulation. Results: Two genes for α-subunit, one for β-subunit and six for γ-subunit were identified and annotated. Bioinformatic analysis confirmed the presence of typical conserved domains in these genes. Furthermore, transcriptional profiling displayed marked differences in expression kinetics of subunits among the selected strains. The expression of AMPK genes decreased rapidly in WJ11, high lipid producer strain during the lipid accumulation phase while contrasting profile of expression was observed in CBS 277.49, low lipid producer strain. Conclusion: The present study has shown the association of AMPK genes with lipid metabolism at the transcriptional level. The involvement of Snf-α1, Snf-α2, Snf-β, Snf-γ1, Snf-γ4, Snf-γ5 subunits were shown to be more pronounced and could potentially be further explored in future studies. [ABSTRACT FROM AUTHOR]

Fusobacterium nucleatum , a pathobiont inhabiting the oral cavity, contributes to opportunistic diseases, such as periodontal diseases and gastrointestinal cancers, which involve microbiota imbalance. Broad-spectrum antimicrobial agents, while effective against F. nucleatum infections, can exacerbate dysbiosis. This necessitates the discovery of more targeted narrow-spectrum antimicrobial agents. We therefore investigated the potential for the fusobacterial enoyl-ACP reductase II (ENR II) isoenzyme Fn FabK (C4N14&#95; 04250) as a narrow-spectrum drug target. ENRs catalyze the rate-limiting step in the bacterial fatty acid synthesis pathway. Bioinformatics revealed that of the four distinct bacterial ENR isoforms, F. nucleatum specifically encodes Fn FabK. Genetic studies revealed that fabK was indispensable for F. nucleatum growth, as the gene could not be deleted, and silencing of its mRNA inhibited growth under the test conditions. Remarkably, exogenous fatty acids failed to rescue growth inhibition caused by the silencing of fabK . Screening of synthetic phenylimidazole analogues of a known FabK inhibitor identified an inhibitor (i.e., 681) of Fn FabK enzymatic activity and F. nucleatum growth, with an IC 50 of 2.1 μM (1.0 μg/mL) and a MIC of 0.4 μg/mL, respectively. Exogenous fatty acids did not attenuate the activity of 681 against F. nucleatum . Furthermore, Fn FabK was confirmed as the intracellular target of 681 based on the overexpression of Fn FabK shifting MICs and 681-resistant mutants having amino acid substitutions in Fn FabK or mutations in other genetic loci affecting fatty acid biosynthesis. 681 had minimal activity against a range of commensal flora, and it was less active against streptococci in physiologic fatty acids. Taken together, Fn FabK is an essential enzyme that is amenable to drug targeting for the discovery and development of narrow-spectrum antimicrobial agents.

Quinoa is rich in nutrients, high in oil content and ideal in fatty acid composition. It is a potential resource for oil extract. Plant oil is mainly stored in crop seeds and fruits in the form of triacylglycerol, and the biosynthesis of oil is catalyzed by a large set of enzymes and regulated by both environmental factors and related genes. In addition, the synthesis and storage of oil involve plaslid, endoplasmic reticulum and oil body. The molecular mechanism related to the synthesis of quinoa oil will provide a basis for breeding of oil-quinoa. In this study, the transcriptome of quinoa was analyzed. Based on quinoa transcriptome data, genes involved in fatty acids biosynthesis were explored, and the expression pattern of quinoa genes related to acetyl CoA carboxylase and β-ketoacyl ACP synthase were analyzed. The results were as follows: There were 87 genes related to fatty acid biosynthesis in quinoa, involving key enzymes such as acetyl CoA carboxylase and β-kdoacyl ACP synthase. The number of long-chain acyl-CoA synthdase gene was the most, followed by the β-oxoacyl-ACP reductase gene. Through pathway enrichment analysis, all of these differentially expressed genes were classified into pathways including fatty acid biosynthesis and fatty acid metabolism which were involved in oil synthesis. Based on gene expression pattern analysis, it was found that the genes related to fatty acid biosynthesis showed up-regulalion in quinoa Seed, which was closely related to the production and accumulation of oil in Seed. The accD gene was not differentially expressed between different tissues, indicating that the β-CT subunit may not be a limitation affecting factor for the function of acdyl-CoA carboxylase. The α-CT protein encoded by accD gene, with no signal peptide and was a hydrophobic protein. However, β-CT was a hydrophilic protein. KAS II contained a conserved domain, and QcFb1S, QcFb4S and QcFb7S were up-regulated in Seeds, which were related to the chain extension of quinoa fatty acids and oil formation. The excavation of genes related to fatty acid biosynthesis pathway of quinoa will provide a theordical basis for the study of the synthesis and accumulation of oil, and it has important enlightenment for the follow-up research of high oil quinoa varieties. [ABSTRACT FROM AUTHOR]

Fatty acids are involved in the development and progression of colorectal cancer (CRC). However, genetic effects of fatty acid biosynthesis pathway on CRC outcome are unclear. Cox regression model was used to evaluate genetic effects on CRC overall survival (OS) and progression‐free survival (PFS), accompanied by calculating hazard ratios (HRs) and confidence intervals (CIs). Differential expression analysis, expression quantitative trait loci analysis, dual‐luciferase reporter assay and chromatin immunoprecipitation assay were performed to explore the genetically biological mechanism. The rs10838164 C>T in HSD17B12 was significantly associated with an increased risk of death and progression of CRC (OS, HR = 2.12, 95% CI = 1.40‐3.22, P = 4.03 × 10−4; PFS, HR = 1.64, 95% CI = 1.11‐2.44, P = 1.35 × 10−2), of which T allele could increase HSD17B12 expression (P = 1.78 × 10−11). Subsequently, the functional experiments indicated that rs10838164 T allele could not only enhance the binding affinity of transcription factor YY1 to HSD17B12 region harbouring rs10838164 but also promote the transcriptional activity of HSD17B12, which was significantly up‐regulated in colorectal tumour tissues. Our findings suggest that genetic variants in fatty acid biosynthesis pathway play an important role in CRC outcome. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, is the world’s leading cause of death from an infectious disease. One of the main features of this pathogen is the complex and dynamic lipid composition of the cell envelope, which adapts to the variable host environment and defines the fate of infection by actively interacting with and modulating immune responses. However, while much has been learned about the enzymes of the numerous lipid pathways, little knowledge is available regarding the proteins and metabolic signals regulating lipid metabolism during M. tuberculosis infection. In this work, we constructed and characterized a FasR-deficient mutant in M. tuberculosis and demonstrated that FasR positively regulates fas and acpS expression. Lipidomic analysis of the wild type and mutant strains revealed complete rearrangement of most lipid components of the cell envelope, with phospholipids, mycolic acids, sulfolipids, and phthiocerol dimycocerosates relative abundance severely altered. As a consequence, replication of the mutant strain was impaired in macrophages leading to reduced virulence in a mouse model of infection. Moreover, we show that the fasR mutant resides in acidified cellular compartments, suggesting that the lipid perturbation caused by the mutation prevented M. tuberculosis inhibition of phagolysosome maturation. This study identified FasR as a novel factor involved in regulation of mycobacterial virulence and provides evidence for the essential role that modulation of lipid homeostasis plays in the outcome of M. tuberculosis infection.

Proteome data was obtained from the fruit mesocarps of the two oil palm species, namely, the African Elaeis guineensis (commercial tenera or commonly known as D x P and MPOB-Nigerian tenera) and the South American Elaeis oleifera. Total proteins were extracted from randomly selected fruitlets and subjected to proteomics characterisation by means of liquid chromatography mass spectrometry. Number of proteins identified, the grouping of the biological replicates from five developmental weeks after anthesis, and the localisation of gene corresponded to the detected proteins on the oil palm chromosomes, were presented. A total of 4,116, 4,210 and 4,081 proteins were found in commercial tenera and MPOB Nigerian tenera for Elaeis guineensis; and Elaeis oleifera, respectively. Principal component analysis showed two distinct clusters that corresponded to Elaeis guineensis and Elaeis oleifera. Collectively, genes that corresponded to the identified proteins were found to be located in all 16 oil palm chromosomes. A total of 59 proteins from Elaeis guineensis and Elaeis oleifera were down-regulated for >5-fold change during the peak of lipid biosynthesis compared to the onset. The same comparative analysis revealed that 66 proteins were up-regulated for >5-fold change. About 60.0% of the observed proteins were involved in catalytic activity while 28.5% were associated with redox reaction. Based on same datasets, the tricarboxylic acid cycle and 5-hydroxytryptamine degradation pathways were found to be enriched the most (>36-fold change). These data can be used to support the oil palm gene model validation and lipid metabolism research, particularly in the areas of oil yield and quality. The tabulated protein lists of identified proteins and their expression changes from these varieties were provided as supplementary files. Raw MSF and mzid files for all the oil palm species were deposited in the ProteomeXchange (PXD017436).

Though microalgae have been considered the potential resource for lipid production, native strains are unable to meet the industrial demand. Here, we aim to uncover the complex molecular relationship between algal growth and lipid accumulation. Transcriptomic analysis revealed the crucial role of plastidial fatty acid and triacylglycerol (TAG) biosynthetic machinery in lipid overproduction. The expression of key fatty acid biosynthetic genes such as acetyl-CoA carboxylase (ACCase), malonyl CoA−acyl carrier protein transacylase (MCAT), 3-ketoacyl synthase (KAS), 3-ketoacyl-ACP reductase (KAR) increased during day 10–13 of cultivation, particularly plastidial TAG biosynthetic genes substantially increased. However, expression of genes involved in ER TAG biosynthesis increased only in the stationary phase, which implied the potential of plastidial TAG biosynthesis. This report provides a novel insight into the growth-phase dependent lipogenic orchestration, and also uncovers the signature genes and plastidial TAG biosynthesis that might be extrapolated for improving lipogenic traits of algae.

Little is known about the structure-function relationship of membrane-bound lipid desaturases. Using a domain-swapping strategy, we found that the N terminus (comprising the two first transmembrane segments) region of Bacillus cereus DesA desaturase improves Bacillus subtilis Des activity. In addition, the replacement of the first two transmembrane domains from Bacillus licheniformis inactive open reading frame (ORF) BL02692 with the corresponding domain from DesA was sufficient to resurrect this enzyme. Unexpectedly, we were able to restore the activity of ORF BL02692 with a single substitution (Cys40Tyr) of a cysteine localized in the first transmembrane domain close to the lipid–water interface. Substitution of eight residues (Gly90, Trp104, Lys172, His228, Pro257, Leu275, Tyr282, and Leu284) by site-directed mutagenesis produced inactive variants of DesA. Homology modeling of DesA revealed that His228 is part of the metal binding center, together with the canonical His boxes. Trp104 shapes the hydrophobic tunnel, whereas Gly90 and Lys172 are probably involved in substrate binding/recognition. Pro257, Leu275, Tyr282, and Leu284 might be relevant for the structural arrangement of the active site or interaction with electron donors. This study reveals the role of the N-terminal region of Δ5 phospholipid desaturases and the individual residues necessary for the activity of this class of enzymes.

Currently, very long chain fatty acids (VLCFAs) for oleochemical, pharmaceutical, cosmetic, or food applications are extracted from plant or marine organism resources, which is associated with a negative environmental impact. Therefore, there is an industrial demand to develop sustainable, microbial resources. Due to its ease of genetic modification and well-characterized metabolism, Escherichia coli has established itself as a model organism to study and tailor microbial fatty acid biosynthesis using a concerted genetic engineering approach. In this study, we systematically implemented a plant-derived (Arabidopsis thaliana) enzymatic cascade in Escherichia coli to enable unbranched VLCFA biosynthesis. The four Arabidopsis thaliana membrane-bound VLCFA enzymes were expressed using a synthetic expression cassette. To facilitate enzyme solubilization and interaction of the synthetic VLCFA synthase complex, we applied a self-assembly GFP scaffold. In order to initiate VLCFA biosynthesis, external oleic acid and cerulenin were supplemented to cultures. In this context, we detected the generation of arachidic (20:0), cis-11-eicosenoic (20:1) and cis-13-eicosenoic acid (20:1).

Abstract Background Lipid accumulation by oleaginous microorganisms is of great scientific interest and biotechnological potential. While nitrogen limitation has been routinely employed, low-cost raw materials usually contain rich nitrogenous components, thus preventing from efficient lipid production. Inorganic phosphate (Pi) limitation has been found sufficient to promote conversion of sugars into lipids, yet the molecular basis of cellular response to Pi limitation and concurrent lipid accumulation remains elusive. Results Here, we performed multi-omic analyses of the oleaginous yeast Rhodosporidium toruloides to shield lights on Pi-limitation-induced lipid accumulation. Samples were prepared under Pi-limited as well as Pi-repleted chemostat conditions, and subjected to analysis at the transcriptomic, proteomic, and metabolomic levels. In total, 7970 genes, 4212 proteins, and 123 metabolites were identified. Results showed that Pi limitation facilitates up-regulation of Pi-associated metabolism, RNA degradation, and triacylglycerol biosynthesis while down-regulation of ribosome biosynthesis and tricarboxylic acid cycle. Pi limitation leads to dephosphorylation of adenosine monophosphate and the allosteric activator of isocitrate dehydrogenase key to lipid biosynthesis. It was found that NADPH, the key cofactor for fatty acid biosynthesis, is limited due to reduced flux through the pentose phosphate pathway and transhydrogenation cycle and that this can be overcome by over-expression of an endogenous malic enzyme. These phenomena are found distinctive from those under nitrogen limitation. Conclusions Our data suggest that Pi limitation activates Pi-related metabolism, RNA degradation, and TAG biosynthesis while inhibits ribosome biosynthesis and TCA cycle, leading to enhanced carbon fluxes into lipids. The information greatly enriches our understanding on microbial oleaginicity and Pi-related metabolism. Importantly, systems data may facilitate designing advanced cell factories for production of lipids and related oleochemicals.

Abstract Background Perilla frutescens is well known for its high α-linolenic acid (ALA) accumulation in seeds and medicinal values as well as a source of edible and general-purpose oils. However, the regulatory mechanisms of the biosynthesis of fatty acid in its seeds remain poorly understood due to the lacking of sequenced genome. For better understanding the regulation of lipid metabolism and further increase its oil content or modify oil composition, time-course transcriptome and lipid composition analyses were performed. Results Analysis of fatty acid content and composition showed that the α-linolenic acid and oleic acid accumulated rapidly from 5 DAF to 15 DAF and then kept relatively stable. However, the amount of palmitic acid and linoleic acid decreased quickly from 5 DAF to 15DAF. No significant variation of stearic acid content was observed from 5 DAF to 25DAF. Our transcriptome data analyses revealed that 110,176 unigenes were generated from six seed libraries at 5, 10, 20 DAF. Of these, 53 (31 up, 22 down) and 653 (259 up, 394 down) genes showed temporal and differentially expression during the seed development in 5 DAF vs 10 DAF, 20 vs 10 DAF, respectively. The differentially expressed genes were annotated and found to be involved in distinct functional categories and metabolic pathways. Deep mining of transcriptome data led to the identification of key genes involved in fatty acid and triacylglycerol biosynthesis and metabolism. Thirty seven members of transcription factor family AP2, B3 and NFYB putatively involved in oil synthesis and deposition were differentially expressed during seed development. The results of qRT-PCR for selected genes showed a strong positive correlation with the expression abundance measured in RNA-seq analysis. Conclusions The present study provides valuable genomic resources for characterizing Perilla seed gene expression at the transcriptional level and will extend our understanding of the complex molecular and cellular events of oil biosynthesis and accumulation in oilseed crops.

Mycobacterium tuberculosis , the etiologic agent of human tuberculosis, is the world's leading cause of death from an infectious disease. One of the main features of this pathogen is the complex and dynamic lipid composition of the cell envelope, which adapts to the variable host environment and defines the fate of infection by actively interacting with and modulating immune responses. However, while much has been learned about the enzymes of the numerous lipid pathways, little knowledge is available regarding the proteins and metabolic signals regulating lipid metabolism during M. tuberculosis infection. In this work, we constructed and characterized a FasR-deficient mutant in M. tuberculosis and demonstrated that FasR positively regulates fas and acpS expression. Lipidomic analysis of the wild type and mutant strains revealed complete rearrangement of most lipid components of the cell envelope, with phospholipids, mycolic acids, sulfolipids, and phthiocerol dimycocerosates relative abundance severely altered. As a consequence, replication of the mutant strain was impaired in macrophages leading to reduced virulence in a mouse model of infection. Moreover, we show that the fasR mutant resides in acidified cellular compartments, suggesting that the lipid perturbation caused by the mutation prevented M. tuberculosis inhibition of phagolysosome maturation. This study identified FasR as a novel factor involved in regulation of mycobacterial virulence and provides evidence for the essential role that modulation of lipid homeostasis plays in the outcome of M. tuberculosis infection. [ABSTRACT FROM AUTHOR]

Background: Caldicellulosiruptor bescii, a promising biocatalyst being developed for use in consolidated bioprocessing of lignocellulosic materials to ethanol, grows poorly and has reduced conversion at elevated medium osmolarities. Increasing tolerance to elevated fermentation osmolarities is desired to enable performance necessary of a consolidated bioprocessing (CBP) biocatalyst. Results: Two strains of C. bescii showing growth phenotypes in elevated osmolarity conditions were identified. The first strain, ORCB001, carried a deletion of the FapR fatty acid biosynthesis and malonyl-CoA metabolism repressor and had a severe growth defect when grown in high-osmolarity conditions—introduced as the addition of either ethanol, NaCl, glycerol, or glucose to growth media. The second strain, ORCB002, displayed a growth rate over three times higher than its genetic parent when grown in high-osmolarity medium. Unexpectedly, a genetic complement ORCB002 exhibited improved growth, failing to revert the observed phenotype, and suggesting that mutations other than the deleted transcription factor (the fruR/cra gene) are responsible for the growth phenotype observed in ORCB002. Genome resequencing identified several other genomic alterations (three deleted regions, three substitution mutations, one silent mutation, and one frameshift mutation), which may be responsible for the observed increase in osmolarity tolerance in the fruR/cra-deficient strain, including a substitution mutation in dnaK, a gene previously implicated in osmoresistance in bacteria. Differential expression analysis and transcription factor binding site inference indicates that FapR negatively regulates malonyl-CoA and fatty acid biosynthesis, as it does in many other bacteria. FruR/Cra regulates neighboring fructose metabolism genes, as well as other genes in global manner. Conclusions: Two systems able to effect tolerance to elevated osmolarities in C. bescii are identified. The first is fatty acid biosynthesis. The other is likely the result of one or more unintended, secondary mutations present in another transcription factor deletion strain. Though the locus/loci and mechanism(s) responsible remain unknown, candidate mutations are identified, including a mutation in the dnaK chaperone coding sequence. These results illustrate both the promise of targeted regulatory manipulation for osmotolerance (in the case of fapR) and the challenges (in the case of fruR/cra). [ABSTRACT FROM AUTHOR]

In Arabidopsis thaliana, AtMYB76 is an MYB transcription factor that has been shown to play multiple roles in the biosynthesis of aliphatic glucosinolates and fatty acids. However, in Brassica napus, the role of BnaA10.SOI.a, an AtMYB76 orthologue, in the accumulation of seed lipids remains unclear. In the present study, we obtained the BnaA10.SOI.a coding domain sequence from the Brassica napus cultivar 'Zhongshuang 11' and analysed its conserved protein domain. A subcellular localization experiment in tobacco leaf cells indicated that BnaA10.SOI.a functioned as a transcription factor. Our results demonstrated that the introduction of BnaA10.SOI.a into an Arabidopsis thaliana myb76‐2 mutant could restore wild‐type levels of seed fatty acid content. Moreover, the expression levels of six oil biosynthetic genes in developing seeds of myb76‐2 were restored to wild‐type levels by ectopic expression of BnaA10.SOI.a. These results improve our understanding of the function of BnaA10.SOI.a and provide a potential target for genetic manipulations of B. napus to improve oil quantity in seeds. [ABSTRACT FROM AUTHOR]

Chronic or non-communicable diseases are the leading cause of death worldwide; they usually result in long-term illnesses and demand long-term care. Despite advances in molecular therapeutics, specific biomarkers and targets for the treatment of these diseases are required. The dysregulation of de novo lipogenesis has been found to play an essential role in cell metabolism and is associated with the development and progression of many chronic diseases; this confirms the link between obesity and various chronic diseases. The main enzyme in this pathway—ATP-citrate lyase (ACLY), a lipogenic enzyme—catalyzes the critical reaction linking cellular glucose catabolism and lipogenesis. Increasing lines of evidence suggest that the modulation of ACLY expression correlates with the development and progressions of various chronic diseases such as neurodegenerative diseases, cardiovascular diseases, diabetes, obesity, inflammation, and cancer. Recent studies suggest that the inhibition of ACLY activity modulates the glycolysis and lipogenesis processes and stimulates normal physiological functions. This comprehensive review aimed to critically evaluate the role of ACLY in the development and progression of different diseases and the effects of its downregulation in the prevention and treatment of these diseases. [ABSTRACT FROM AUTHOR]

Trichosporon cutaneum, a dimorphic oleaginous yeast, has immense biotechnological potential, which can use lignocellulose hydrolysates to accumulate lipids. Our preliminary studies on its dimorphic transition suggested that pH can significantly induce its morphogenesis. However, researches on dimorphic transition correlating with lipid biosynthesis in oleaginous yeasts are still limited. In this study, the unicellular yeast cells induced under pH 6.0–7.0 shake flask cultures resulted in 54.32% lipid content and 21.75 g/L dry cell weight (DCW), so lipid production was over threefold than that in hypha cells induced by acidic condition (pH 3.0–4.0). Furthermore, in bioreactor batch cultivation, the DCW and lipid content in unicellular yeast cells can reach 21.94 g/L and 58.72%, respectively, both of which were also more than twofold than that in hypha cells. Moreover, the activities of isocitrate dehydrogenase (IDH), malic enzyme (MAE), isocitrate lyase (ICL) and ATP citrate lyase (ACL) in unicellular cells were all higher than in the hyphal cells. In the meanwhile, the transcriptome data showed that the genes related to fatty acid biosynthesis, carbon metabolism and encoded Rim101 and cAMP–PKA signaling transduction pathways were significantly up-regulated in unicellular cells, which may play an important role in enhancing the lipid accumulation. In conclusion, our results provided insightful information focused on the molecular mechanism of dimorphic transition and process optimization for enhancing lipid accumulation in T. cutaneum. [ABSTRACT FROM AUTHOR]

Obesity that is highly associated with numerous metabolic diseases has become a global health issue nowdays. Plant sesterterpenoids are an important group of natural products with great potential; thus, their bioactivities deserve extensive exploration. RNA-seq analysis indicated that leucosceptroid B, a sesterterpenoid previously discovered from the glandular trichomes of Leucosceptrum canum , significantly regulated the expression of 10 genes involved in lipid metabolism in Caenorhabditis elegans. Furthermore, leucosceptroid B was found to reduce fat storage, and downregulate the expression of two stearoyl-CoA desaturase (SCD) genes fat-6 and fat-7 , and a fatty acid elongase gene elo-2 in wild-type C. elegans. In addition, leucosceptroid B significantly decreased fat accumulation in both fat-6 and fat-7 mutant worms but did not affect the fat storage of fat-6 ; fat-7 double mutant. These findings indicated that leucosceptroid B reduced fat storage depending on the downregulated expression of fat-6 , fat-7 and elo-2 and thereby inhibiting the biosynthesis of the corresponding unsaturated fatty acid. These findings provide new insights into the development and utilization of plant sesterterpenoids as potential antilipemic agents. [ABSTRACT FROM AUTHOR]

We hypothesized that a low phytosterol oil, such as soybean oil, in combination with an α-linolenic acid (ALA) rich oil, such as linseed oil, and supplemental cholesterol could effectively replace fish oil in salmonid feeds. As such, the primary objective was to blend soybean oil with linseed oil and supplemental cholesterol to maintain fish growth and increase de novo production of the omega-3 fatty acids (n-3 FA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in trout muscle, since EPA and DHA have been identified as beneficial nutrients in human nutrition, and farmed seafood must meet consumer needs and expectations. To accomplish this, we used soy oil for its low phytosterol properties in combination with linseed oil for its n-3 FA content, with and without cholesterol to improve utilization. Upon conclusion of the study, our results did not support our hypothesis. Trout fed plant-based diets containing any amount of soy oil had reduced growth performance. Only fish fed the plant-based diet with 100% linseed oil plus supplemental cholesterol grew as well as both control groups, fishmeal/fish oil and plant meal/fish oil. Dietary cholesterol supplementation increased plasma cholesterol levels and EPA in fillets (P < 0.05). Two-way ANOVA demonstrated that growth performance and muscle EPA content were significantly increased in fish fed cholesterol-supplemented diets. However, expression of genes involved in fatty acid biosynthesis were not enhanced by cholesterol, suggesting a potential disconnect between gene expression and functional activity. Although our hypothesis failed and soybean oil was found to be less accepted by the fish, resulting in lower growth and feed intake, we were successful in developing a high soy-protein diet (35%) with all-plant ingredients using linseed oil and supplemental cholesterol that resulted in equal fish performance to fish fed a fishmeal/fish oil control diet. More research is needed to identify a cost-effective EPA/DHA source to meet consumer needs and expectations for n-3 FA in trout fillets. • Supplemental cholesterol improved trout growth when fed a plant-based diet. • The L100 + C group achieved similar growth to the FM/FO control. • Dietary soy oil to linseed oil ratio did not affect plasma cholesterol level. • Cholesterol supplementation significantly increased EPA levels in fillets. [ABSTRACT FROM AUTHOR]

Chaihu Shugan powder (CSP) plays an important role in the prevention and treatment of nonalcoholic fatty liver disease (NAFLD) through a variety of biological mechanisms. However, whether the mechanism involves microRNA (miRNA) regulation remains unknown. To investigate the effects of CSP on the miRNA expression profile of rats with NAFLD induced by high-fat diet (HFD), and to explore the mechanism of CSP in the treatment of NAFLD. NAFLD rat models were established by an 8-week HFD. The therapeutic effects of CSP on NAFLD were evaluated by physiological, biochemical and pathological analysis and hepatic surface microcirculation perfusion test. MicroRNA sequencing was used to study the effect of CSP on the miRNA expression profile of NAFLD rats, and the target genes of differentially expressed (DE) miRNAs were predicted for further function enrichment analysis. Next, targets of CSP and NAFLD were collected by a network pharmacological approach, and Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis were performed for the common target genes of CSP, NAFLD and DE miRNAs, and the expression levels of key genes and proteins were verified by quantitative Real-time PCR and Western blot. Finally, a network among formula-herb-compound-miRNA-target-biological processes-disease was established to explained the complex regulation mechanism of CSP on NAFLD. The results showed that CSP significantly improved liver lipid accumulation, serum lipid and transaminase levels and liver surface microcirculation disturbance in HFD-induced NAFLD rats. The intervention of CSP reversed the high expression of 15 miRNAs in liver tissues induced by HFD, including miR-34a-5p, miR-146a-5p, miR-20b-5p and miR-142-3p. The results of pathway and functional enrichment analysis showed that, CSP might play an anti-NAFLD role via regulating DE miRNAs related to fatty acid metabolic process. Combined with the network pharmacological analysis, it was found that the DE miRNAs might affected the fatty acid biosynthesis pathway in the treatment of NAFLD by CSP. Molecular biology experiments have conformed the decreased the gene and protein levels of acetyl-CoA carboxylase alpha (ACACA), fatty acid synthase (FASN) and other fatty acid biosynthesis related enzymes on NAFLD rats after intervention of CSP. CSP can significantly reduce hepatic lipid accumulation of NAFLD rat model induced by HFD, and its mechanism may be through the action of 15 miRNAs such as miR-34a-5p, miR-146a-5p, miR-20b-5p and miR-142-3p. Reduce the gene and protein expression levels of ACACA, FASN and other fatty acid biosynthesis related enzymes, thus reducing fatty acid biosynthesis. Based on an epigenetic perspective, this study explains the key anti-NAFLD mechanism of CSP via combination of microRNA sequencing and network pharmacological analysis, providing a new reference for the modernization of traditional Chinese medicine. [Display omitted] • Chaihu Shugan powder improves lipid accumulation and liver function impairment in NAFLD rats. • Chaihu Shugan powder promotes remodeling microRNAome in NAFLD rats. • Chaihu Shugan powder might play an anti-NAFLD effect via inhibiting the biological process of fatty acid biosynthesis. [ABSTRACT FROM AUTHOR]

The liver plays a key role in whole-body, glucose and lipid homeostasis. Nutritional signals in response to fasting and refeeding regulate hepatic lipid synthesis. It is established that activation of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1) in response to overnutrition regulates MAPK-dependent pathways that control lipid metabolism in the liver. However, the regulatory mechanisms and the impact of the actions of MKP-1 in hepatic response to fasting remains unclear. We investigated the effect of fasting on the expression of MKP-1 and the impact on hepatic response to feeding. In this study, we demonstrate that fasting stress induced upregulation of hepatic MKP-1 protein levels with a corresponding downregulation of p38 MAPK and JNK phosphorylation in mouse livers. We found that MKP-1-deficient livers are resistant to fasting-induced hepatic steatosis. Hepatic MKP-1 deficiency impaired fasting-induced changes in the levels of key transcription factors involved in the regulation of fatty acid and cholesterol metabolism including Srebf2 and Srebf1c. Mechanistically, MKP-1 negatively regulates Srebf2 expression by attenuating p38 MAPK pathway, suggesting its contribution to the metabolic effects of MKP-1 deficiency in the fasting liver. These findings support the hypothesis that upregulation of MKP-1 is a physiological relevant response and might be beneficial in hepatic lipid utilization during fasting in the liver. Collectively, these data unravel some of the complexity and tissue specific interaction of MKP-1 action in response to changes in nutritional cues, including fasting and excess nutrients

Abstract Background Trophic interactions are a fundamental aspect of ecosystem functioning, but often difficult to observe directly. Several indirect techniques, such as fatty acid analysis, were developed to assess these interactions. Fatty acid profiles may indicate dietary differences, while individual fatty acids can be used as biomarkers. Ants are among the most important terrestrial animal groups, but little is known about their lipid metabolism, and no study so far used fatty acids to study their trophic ecology. We set up a feeding experiment with high- and low-fat food to elucidate patterns and dynamics of neutral lipid fatty acids (NLFAs) assimilation in ants. We asked whether dietary fatty acids are assimilated through direct trophic transfer, how diet influences NLFA total amounts and patterns over time, and whether these assimilation processes are similar across species and life stages. Results Ants fed with high-fat food quickly accumulated specific dietary fatty acids (C18:2n6, C18:3n3 and C18:3n6), compared to ants fed with low-fat food. Dietary fat content did not affect total body fat of workers or amounts of fatty acids extensively biosynthesized by animals (C16:0, C18:0, C18:1n9). Larval development had a strong effect on the composition and amounts of C16:0, C18:0 and C18:1n9. NLFA compositions reflected dietary differences, which became more pronounced over time. Assimilation of specific dietary NLFAs was similar regardless of species or life stage, but these factors affected dynamics of other NLFAs, composition and total fat. Conclusions We showed that ants accumulated certain dietary fatty acids via direct trophic transfer. Fat content of the diet had no effect on lipids stored by ants, which were able to synthesize high amounts of NLFAs from a sugar-based diet. Nevertheless, dietary NLFAs had a strong effect on metabolic dynamics and profiles. Fatty acids are a useful tool to study trophic biology of ants, and could be applied in an ecological context, although factors that affect NLFA patterns should be taken into account. Further studies should address which NLFAs can be used as biomarkers in natural ant communities, and how factors other than diet affect fatty acid dynamics and composition of species with distinct life histories.

Palmitoleic acid is an unusual omega-7 monounsaturated fatty acid that occurs naturally in high levels in macadamia plants. Due to its wide public acceptance and being a commonly occurring food, macadamia nuts may serve as an important dietary agent for the delivery of palmitoleic acid to the human body. This review focuses on discussing the biological functions of palmitoleic acid, the association of palmitoleic acid with various diseases, as well as the anticipated biosynthetic pathway of palmitoleic acid in macadamia plants. In addition, given the importance to regulate palmitoleic acid contents in macadamia to achieve improved nutrition and commercial value, this review also proposes GWAS as an effective strategy to identify the candidate genes responsible for the accumulation of palmitoleic acid in macadamia nuts.