Synthesis Of Long-chain Fatty Acids Research Articles

Synthesis and optimization of long-chain fatty acids via the oxidation of long-chain fatty alcohols

Abstract The oxidation of long-chain fatty alcohols with Jones reagent to prepare long-chain fatty acids is an efficient and economical method. The by-product of chromium sulfate is electrolyzed and oxidized to hexavalent chromium, which is recycled to avoid the emission of toxic by-products. In this article, the process conditions for the preparation of carboxylic acid by chromium reagent oxidizing alcohol are optimized, and the effects of various reaction conditions on the experiment are explored. Innovatively, the reaction was optimized by reverse addition. The two synthesis methods are compared by orthogonal experiments, and the optimal reaction conditions for oxidation are determined: the organic solvent of alcohol is added to the acidified Jones reagent by reverse addition; the amount of chromium reagent is 1.5 times the required stoichiometry; the chromium concentration in chromium reagent is 2.5 mol·L−1; the reaction temperature was lower than 30°C and the reaction time was 4 h. Under the optimized reaction conditions, the formation of by-products was effectively inhibited, and the conversion rate of alcohol oxidation to carboxylic acid was increased from 80% to more than 90%.

Prebiotic Synthesis of Microdroplets from Formate over a Bimetallic Cobalt-Nickel Nanomotif.

The hypothesis underlying the abiogenic origin of life suggests that the nonenzymatic synthesis of long-chain fatty acids led to the construction of vesicles for compartmentalization in an early stage during the transition from geochemistry to biochemistry. However, evidence for this theory remains elusive as C5+ carboxylic acids cannot be synthesized using current laboratory simulations. Here, we report the synthesis of long-chain carboxylic acids (C3-C7) with a 42 mmol/gCo+Ni yield and 87.7% selectivity from formate (an intermediate of the acetyl-CoA pathway) over a cobalt-nickel alloy under alkaline hydrothermal conditions and the subsequent formation of microdroplets from organics. Density functional theory (DFT) calculations confirmed that the synergistic effect of the bimetal catalyst is key for catalyzing C-C coupling. Investigations by infrared spectroscopy, electron paramagnetic resonance, and isotope-labeled experiments revealed that HCO* serves as a reaction intermediate and is involved in the subsequent elementary steps for synthesizing long-chain carboxylic acids from formate. Taken together, these findings may help explain how the first protocells emerged geochemically and provide support for the hypothesis of the abiogenic origin of life. The hydrothermal system developed may also be applicable for the sustainable synthesis of long-chain carboxylates from one-carbon substrates using nonnoble metal catalysts.

PaMYB11 promotes suberin deposition in Norway spruce embryogenic tissue during cryopreservation: A novel resistance mechanism against osmosis.

The osmotic resistance mechanism has been extensively studied in whole plants or plant tissues. However, little is known about it in embryogenic tissue (ET) which is widely used in plant-based biotechnological systems. Suberin, a cell wall aliphatic and aromatic heteropolymer, plays a critical role in plant cells against osmosis stress. The suberin regulatory biosynthesis has rarely been studied in gymnosperms. Here, PaMYB11, a subgroup 11 R2R3-MYB transcription factor, plays a key role in the osmotic resistance of Norway spruce (Picea abies) ETs during cryoprotectant pretreatment. Thus, RNA-seq, histological, and analytical chemical analyses are performed on the stable transformations of PaMYB11-OE and PaMYB11-SRDX in Norway spruce ETs. DAP-seq, Y1H, and LUC are further combined to explore the PaMYB11 targets. Activation of PaMYB11 is necessary and sufficient for suberin lamellae deposition on Norway spruce embryogenic cell walls, which plays a decisive role in ET survival under osmotic stress. Transcriptome analysis shows that PaMYB11 enhances suberin lamellae monomer synthesis by promoting very long-chain fatty acid (VLCFA) synthesis. PaPOP, PaADH1, and PaTET8L, the first two (PaADH1 and PaPOP, included) involved in VLCFA synthesis, are proved to be the direct targets of PaMYB11. Our study identified a novel osmotic response directed by PaMYB11 in Norway spruce ET, which provides a new understanding of the resistance mechanism against osmosis in gymnosperms.

PASTICCINO2 interacting with Golgi Anti-Apoptotic Proteins resists endoplasmic reticulum stress dependent on very long-chain fatty acids.

The endoplasmic reticulum (ER) is crucial for maintaining cell homeostasis because it is the primary site for synthesizing secreted and transmembrane proteins and lipids. The unfolded protein response (UPR) is activated to restore ER homeostasis under ER stress. However, the relationship between lipids and the ER stress response in plants is not well understood. Arabidopsis Golgi anti-apoptotic proteins (GAAPs) are involved in resisting ER stress. To elucidate the function of GAAPs, PASTICCINO2 (PAS2), involved in very long-chain fatty acid (VLCFA) synthesis, was found to interact with GAAPs and IRE1. Single pas2 and gaap1/gaap2pas2 double mutants exhibited increased seedling damage and impaired UPR response under chronic ER stress. Site mutation combined with genetic analysis revealed that the role of PAS2 in resisting ER stress depended on its VLCFA synthesis domain. VLCFA contents were upregulated under ER stress, which required GAAPs. Exogenous VLCFAs partially restored the defect in UPR upregulation caused by PAS2 or GAAP mutations under chronic ER stress. These findings demonstrate that the association of PAS2 with GAAPs confers plant resistance to ER stress by regulating VLCFA synthesis and the UPR. This provides a basis for further studies on the connection between lipids and cell fate decisions under stress.

Silencing the fatty acid elongase gene elovl6 induces reprogramming of nutrient metabolism in male Oreochromis niloticus

Elongation of very long-chain fatty acids protein 6 (ELOVL6) plays a pivotal role in the synthesis of endogenous fatty acids, influencing energy balance and metabolic diseases. The primary objective of this study was to discover the molecular attributes and regulatory roles of ELOVL6 in male Nile tilapia, Oreochromis niloticus. The full-length cDNA of elovl6 was cloned from male Nile tilapia, and was determined to be 2255-bp long, including a 5′-untranslated region of 193 bp, a 3′-untranslated region of 1252 bp, and an open reading frame of 810 bp encoding 269 amino acids. The putative protein had typical features of ELOVL proteins. The transcript levels of elovl6 differed among various tissues and among fish fed with different dietary lipid sources. Knockdown of elovl6 in Nile tilapia using antisense RNA technology resulted in significant alterations in hepatic morphology, long-chain fatty acid synthesis, and fatty acid oxidation, and led to increased fat deposition in the liver and disrupted glucose/lipid metabolism. A comparative transcriptomic analysis (elovl6 knockdown vs. the negative control) identified 5877 differentially expressed genes with significant involvement in key signaling pathways including the peroxisome proliferator-activated receptor signaling pathway, fatty acid degradation, glycolysis/gluconeogenesis, and the insulin signaling pathway, all of which are crucial for lipid and glucose metabolism. qRT-PCR analyses verified the transcript levels of 13 differentially expressed genes within these pathways. Our findings indicate that elovl6 knockdown in male tilapia impedes oleic acid synthesis, culminating in aberrant nutrient metabolism.

Effects of temperature on the growth, total lipid content and fatty acid composition of Skeletonema dohrnii

The potential of diatoms as aquatic bait, attribute to their abundance in highly unsaturated fatty acids, has been extensively studied. Temperature plays a crucial role in the synthesis of these fatty acids. This study specifically investigated the impact of temperature on the growth, total lipid content, and fatty acid composition of Skeletonema dohrnii, a planktonic diatom commonly associated with red tides and water blooms in China. The aim is to evaluate its suitability as an aquatic bait and provide insights for large-scale factory farming. Results indicated that the highest biomass and maximum growth rate occurred at 28°C, with no significant deviation from the control group at 25°C. At 28°C and 15°C, there was a significant increase in the total lipid content and the total fatty acid content, with a more pronounced effect at 15°C. At 28°C, EPA and DHA content measured at 0.97 ± 0.01 mg.DW.L-1 and 0.264 ± 0.01 mg.DW.L-1 respectively, surpass those at 15°C due to lower biomass. Conversely, at 15°C, substantial synthesis of long-chain polyunsaturated fatty acids, with EPA constituting up to 32.24 ± 0.24% of the total fatty acids, is observed. Modulating the temperature could optimize the utilization of S. dohrnii as an aquatic feed source. These findings underscore the potential of S. dohrnii as a high-quality aquafeed and lay the groundwork for its success in ocean warming scenarios.

Hepatocyte-Specific Fads1 Overexpression Attenuates Western Diet-Induced Metabolic Phenotypes in a Rat Model.

Fatty acid desaturase 1 (FADS1) is a rate-limiting enzyme in long-chain polyunsaturated fatty acid (LCPUFA) synthesis. Reduced activity of FADS1 was observed in metabolic dysfunction-associated steatotic liver disease (MASLD). The aim of this study was to determine whether adeno-associated virus serotype 8 (AAV8) mediated hepatocyte-specific overexpression of Fads1 (AAV8-Fads1) attenuates western diet-induced metabolic phenotypes in a rat model. Male weanling Sprague-Dawley rats were fed with a chow diet, or low-fat high-fructose (LFHFr) or high-fat high-fructose diet (HFHFr) ad libitum for 8 weeks. Metabolic phenotypes were evaluated at the endpoint. AAV8-Fads1 injection restored hepatic FADS1 protein levels in both LFHFr and HFHFr-fed rats. While AAV8-Fads1 injection led to improved glucose tolerance and insulin signaling in LFHFr-fed rats, it significantly reduced plasma triglyceride (by ~50%) and hepatic cholesterol levels (by ~25%) in HFHFr-fed rats. Hepatic lipidomics analysis showed that FADS1 activity was rescued by AAV8-FADS1 in HFHFr-fed rats, as shown by the restored arachidonic acid (AA)/dihomo-γ-linolenic acid (DGLA) ratio, and that was associated with reduced monounsaturated fatty acid (MUFA). Our data suggest that the beneficial role of AAV8-Fads1 is likely mediated by the inhibition of fatty acid re-esterification. FADS1 is a promising therapeutic target for MASLD in a diet-dependent manner.

FASN-mediated fatty acid biosynthesis remodels immune environment in Clonorchis sinensis infection-related intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is the second most common primary liver cancer and is highly lethal. Clonorchis sinensis (C.sinensis) infection is an important risk factor for iCCA. Here we investigated the clinical impact and underlying molecular characteristics of C.sinensis infection-related iCCA. We performed single-cell RNA sequencing, whole-exome sequencing, RNA sequencing, metabolomics and spatial transcriptomics in 251 patients with iCCA from three medical centers. Alterations in metabolism and the immune microenvironment of C.sinensis-related iCCAs were validated through an invitro co-culture system and in a mouse model of iCCA. We revealed that C.sinensis infection was significantly associated with iCCA patients' overall survival and response to immunotherapy. Fatty acid biosynthesis and the expression of fatty acid synthase (FASN), a key enzyme catalyzing long-chain fatty acid synthesis, were significantly enriched in C.sinensis-related iCCAs. iCCA cell lines treated with excretory/secretory products of C.sinensis displayed elevated FASN and free fatty acids. The metabolic alteration of tumor cells was closely correlated with the enrichment of tumor-associated macrophage (TAM)-like macrophages and the impaired function of T cells, which led to formation of an immunosuppressive microenvironment and tumor progression. Spatial transcriptomics analysis revealed that malignant cells were in closer juxtaposition with TAM-like macrophages in C.sinensis-related iCCAs than non-C.sinensis-related iCCAs. Importantly, treatment with a FASN inhibitor significantly reversed the immunosuppressive microenvironment and enhanced anti-PD-1 efficacy in iCCA mouse models treated with excretory/secretory products from C.sinensis. We provide novel insights into metabolic alterations and the immune microenvironment in C.sinensis infection-related iCCAs. We also demonstrate that the combination of a FASN inhibitor with immunotherapy could be a promising strategy for the treatment of C.sinensis-related iCCAs. Clonorchis sinensis (C.sinensis)-infected patients with intrahepatic cholangiocarcinoma (iCCA) have a worse prognosis and response to immunotherapy than non-C.sinensis-infected patients with iCCA. The underlying molecular characteristics of C.sinensis infection-related iCCAs remain unclear. Herein, we demonstrate that upregulation of FASN (fatty acid synthase) and free fatty acids in C.sinensis-related iCCAs leads to formation of an immunosuppressive microenvironment and tumor progression. Thus, administration of FASN inhibitors could significantly reverse the immunosuppressive microenvironment and further enhance the efficacy of anti-PD-1 against C.sinensis-related iCCAs.

Physiology and Mechanism of Milk Fat Globules Secretion in Dairy Animals: A Review

Milk fat globules (MFGs) are a complex compound secreted in the mammary gland, composed of triglycerides; phosphatidylethanolamine (PE) phosphatidylcholine (PC) with unclear mechanism and the fused lipid droplets enclosed by inner layer derived from the endoplasmic reticulum and outer bilayer is directly derived from the apical plasma membrane as the lipid droplets bud out from the cell. The core components of MFGs, triglycerides are synthesized via the de novo fatty acid pathway and LCFA was directly taken from serum. The de novo fatty acid pathway was significantly dependent on the enzymes acetyl-CoA carboxylase (ACACA), fatty acid synthase (FASN) and acyl-CoA synthetase short-chain family member 2 (ACSS2) to synthesize short and medium-chain fatty acids, whereas the bio-hydrogenation pathway is a principal pathway for the synthesis of long-chain fatty acids. Following this, the milk fat globules coated by the membrane are released from the MEC to the lumen with or without other milk components and the membrane that surrounds the fat globule stabilize the milk fat in its dispersed state, prevent flocculation and globule coalescence, and protects against the deleterious effects of lipases. Even though the secretion mechanism of lipid droplets is controversial hormonal and molecular mechanisms are involved. Moreover, the fat globule size and composition are determined by factors such as stage of lactation, physiological state of the animal, Diacylglycerol Acyltransferase1 (DGAT1) activity, and PC/PE ratio along with breed and animal species. While some studies were conducted on milk synthesis and secretion, the molecular mechanism behind lipid droplet fusion, secretion in the apical membrane and how MFGM is formed and the mechanism of MFG synthesis regulation are undiscovered. Therefore, it needs advanced investigation.

RBM45 reprograms lipid metabolism promoting hepatocellular carcinoma via Rictor and ACSL1/ACSL4.

Reprogramming of lipid metabolism during hepatocarcinogenesis is not well elucidated. Here, we aimed to explore pivotal RNA-binding motif proteins (RBMs) in lipid metabolism and their therapeutic potential in hepatocellular carcinoma (HCC). Through bioinformatic analysis, we identified RBM45 as a critical gene of interest among differentially expressed RBMs in HCC, with significant prognostic relevance. RBM45 influenced the malignant biological phenotype and lipid metabolism of HCC cells. Mechanically, RBM45 promotes de novo lipogenesis in HCC by directly targeting two key enzymes involved in long-chain fatty acid synthesis, ACSL1 and ACSL4. RBM45 also targets Rictor, which has been demonstrated to modulate lipid metabolism profoundly. RBM45 also aided lipid degradation through activating a key fatty acid β oxidation enzyme, CPT1A. Thus, RBM45 boosted lipid synthesis and decomposition, indicating an enhanced utility of lipid fuels in HCC. Clinically, body mass index was positively correlated with RBM45 in human HCCs. The combination of a PI3K/AKT/mTOR pathway inhibitor in vitro or Sorafenib in orthotopic liver cancer mouse models with shRBM45 has a more significant therapeutic effect on liver cancer than the drug alone. In summary, our findings highlight the versatile roles of RBM45 in lipid metabolism reprogramming and its therapeutic potential in HCC. Lipids induced RBM45 expression. In turn, RBM45 promoted the utility of lipid in HCCs through accelerating both de novo lipogenesis and fatty acid β oxidation, which required the participation of Rictor, a core component of mTORC2 that has been demonstrated to modulate lipid metabolism potently, as well as ACSL1/ACSL4, two key enzymes of long-chain fatty acid synthesis. When the first-line chemotherapy drug sorafenib is combined with a PI3K/AKT/mTOR pathway inhibitor (MK2206 is an AKT inhibitor, rapamycin is a mTOR inhibitor, and inhibiting RBM45 can significantly inhibit Rictor), cell cycle, proliferation, lipid metabolism reprogramming, and hepatocarcinogenesis can be significantly inhibited, while apoptosis can be significantly enhanced.

Abstract C054: Association of fatty acid synthase expression with FASN gene methylation and self-identified race in prostate cancer

Abstract Fatty acid synthase (FASN) catalyzes the synthesis of long-chain saturated fatty acids and is overexpressed during prostatic tumorigenesis; however, the mechanism of this upregulation remains unclear and could include gene amplification, epigenetic regulation or regulation by androgen receptor (AR). Though FASN is an attractive therapeutic target in prostate cancer and several clinical trials of FASN inhibitors are underway, prior studies have suggested racial disparities in FASN copy number and FASN protein expression exist in primary prostate cancer, which may have implications for the therapeutic efficacy of FASN inhibitors. FASN gene amplification may be more common in prostate cancers from self-identified Black (BL) patients than their White (WH) counterparts, and a recent study has suggested that FASN protein expression is also higher among primary prostate tumors from BL compared to WH men due to changes in the AR cistrome. Here, we examine FASN protein expression as measured by digitally quantified immunohistochemistry assay and reverse phase protein array analysis or FASN gene expression, comparing it to gene CpG methylation pattern by InfiniumEPIC profiling and whole genome bisulfite sequencing (WGBS) across multiple racially diverse primary and metastatic prostate cancer cohorts, including more than 1000 tumors. We demonstrate that the FASN gene body is hypomethylated and overexpressed in primary prostate tumors compared to benign tissue. FASN gene methylation shows a significant inverse correlation with FASN protein and gene expression in both primary and metastatic prostate cancer. However, in contrast to previous studies, we find no significant association of FASN expression or methylation with self-identified race or genetic ancestry in models that include ERG gene fusion status across two independent primary tumor cohorts. Taken together, these data support a potential epigenetic mechanism for FASN regulation in the prostate and suggest that FASN inhibitors may be equally efficacious in both BL and WH men with prostate cancer. Citation Format: Oluwademilade Dairo, Lia DePaula Oliveira, Ethan Schaffer, Thiago Vidotto, Adrianna Amaral De Aragao Mendes, Jiayun Lu, Jessica Hicks, Adam G. Sowalsky, Angelo M. De Marzo, Corrine E. Joshu, Brian Hanratty, Karen S. Sfanos, William B. Isaacs, Michael C. Haffner, Tamara L. Lotan. Association of fatty acid synthase expression with FASN gene methylation and self-identified race in prostate cancer [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C054.

Optimization of Long-Chain Fatty Acid Synthesis from CO 2 Using Response Surface Methodology

A microbial electrosynthesis cell (MES) is an electrochemical technique in which electrolithoautotrophic electroactive microbes fix carbon dioxide (CO2) to longer-chain volatile fatty acids (VFAs). The synthesis of VFAs from CO2 requires optimization to improve the MES performance for industrial feasibility. This work studied the effect of different parameters, such as pH, headspace gas pressure, ethanol concentration, electrolyte, and trace element concentrations, on VFA synthesis from CO2 that used mixed anaerobic consortia in serum bottles. The operational parameters were varied according to a central composite design (CCD) and response surface methodology (RSM). A global optimum for the response variables was determined. The optimum values of different operating factors to maximize VFA production that was obtained from the optimizations were 1.12 × 105 Pa pressure, pH 7.149, ethanol = 2,318.7 mg/L, three times the standard Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ) 300 electrolyte concentration and five times the standard DSMZ 300 trace elements concentration. The experimental study was validated in triplicate, which considered the optimal values. The rate of total VFA production that was obtained from the operational parameters experimental study was 43.7 ± 5.9 mg/L/day under this optimized condition, which agreed with the predicted value of 30.39 mg/L/day. For the media optimization, validation of the experimental study was conducted at the optimal values, and their experimental response was 79.75 ± 19.26 mg/L/day, and the predicted response was 75.89 mg/L/day for total VFA production rates.

Abstract P1160: Genome-wide CRISPR Screen Reveals Genetic And Small Molecule Modifiers Of Ca 2+ -mediated Cell Death

Ca 2+ is a ubiquitous and highly regulated signaling ion in living cells. Thus, Ca 2+ is typically maintained at a low intracellular concentration (10-100 nM), tens of thousands of times lower than the outside space (1-2 mM). Failure to maintain this homeostasis—due to membrane instability or energetic failure—allows supraphysiologic concentrations to enter cells and trigger cell death pathways including mitochondrial permeability transition, apoptosis, and autophagy. This mechanism of cell death is shared by many conditions including myocardial infarction, stroke, and sepsis. Targeting of known protein effectors downstream of Ca 2+ overload, such as caspases and calpains, has not yet translated into therapies due to specificity concerns. Therefore, there is still a pressing need for a comprehensive examination of genetic effectors involved in Ca 2+ -induced cell death. Here, we performed genome-wide CRISPR knockout screening in human cells and identified genes and pathways previously unknown to mediate cell toxicity after Ca 2+ overload. We reveal 115 gene knockouts that protected cells and 9 knockouts that sensitized cells to intracellular Ca 2+ . Notably, genetic ablation of members from the store operated calcium entry, very long-chain fatty acid synthesis, and SWItch/Sucrose Non-Fermentable (SWI/SNF) pathways provided marked protection. Reassuringly, genes known to maintain Ca 2+ homeostasis (e.g., STIM1, ATP2B4, ATP2B1) were recovered by the screen. By comparing against the essential and druggable genomes, we determined that 82 of the protective knockouts are non-essential genes and 21 are targetable with small molecules. Therefore, a significant portion of our hits represent viable but unexplored targets for conditions that feature Ca 2+ overload. We tested this hypothesis using small molecule blockade of hits overlapping with the druggable genome. We found several antagonists that resulted in a reduction of ionomycin-induced cell death. Altogether, our results reveal numerous novel effectors of Ca 2+ -mediated cell death that will serve as a basis for improved mechanistic understanding of cell death and as targets for pharmacotherapeutic design.

Transcriptome analysis of the related defense genes in postharvest Ginkgo biloba seeds against Penicillium oxalicum

Ginkgo biloba seeds (GBSs) are an important homology of medicine and food in China, but are susceptible to infection by Penicillium oxalicum (P. oxalicum) during storage. Despite this, the molecular mechanisms underlying the response of GBSs to P. oxalicum infection remain poorly understood. In this study, we investigated the effects of P. oxalicum infection on GBSs during postharvest storage. We found that P. oxalicum infection increased the respiration rate, electrolyte leakage, and malondialdehyde content, and induced the activities of several defense-related enzymes in GBSs. Transcriptome analysis revealed a total of 17525 differentially expressed genes (DEGs) in GBSs stored at 25 °C, and weighted gene co-expression network analysis (WGCNA) revealed complex defense reactions induced by P. oxalicum infection. These included the upregulation of genes involved in glutathione metabolism, oxidative phosphorylation, long-chain fatty acid synthesis and metabolism, and plant-pathogen interaction. Furthermore, we observed increased expression of DEGs encoding transcription factors such as ERF, WRKY, and MYB. Our findings provide valuable insights into the molecular mechanisms underlying the response of GBSs to P. oxalicum infection during storage, and may facilitate the development of new strategies for maintaining the postharvest quality of GBSs.

Assessing milk response to different combinations of branched-chain volatile fatty acids and valerate in Jersey cows

Some cellulolytic bacteria require 1 or more branched-chain volatile fatty acids (BCVFA) for the synthesis of branched-chain AA and branched-chain long-chain fatty acids because they are not able to uptake branched-chain AA or lack 1 or more enzymes to synthesize branched-chain AA de novo. Supplemental BCVFA and valerate were included previously as a feed additive that was later removed from the market; these older studies and more current studies have noted improvements in neutral detergent fiber digestibility and milk efficiency. However, most studies provided a single BCVFA or else isobutyrate (IB), 2-methylbutyrate (MB), isovalerate, and valerate altogether without exploring optimal combinations. Our objective was to determine a combination of isoacids that is optimal for milk production. Sixty (28 primiparous and 32 multiparous) lactating Jersey cows (106 ± 54 days in milk) were blocked and assigned randomly to either a control (CON) treatment without any isoacids, MB [12.3 mmol/kg dry matter (DM)], MB + IB (7.7 and 12.6 mmol/kg DM of MB and IB, respectively), or all 4 isoacids (6.2, 7.3, 4.2, and 5.1 mmol/kg DM of MB, IB, isovalerate, and valerate, respectively). Cattle were fed the CON treatment for a 2-wk period, then were assigned randomly within a block to treatments for 8 wk (n = 15). There was a trend for an interaction of supplement and parity for milk components. There were no differences in components for primiparous cows, whereas MB + IB tended to increase protein concentration by 0.04 and 0.08 percentage units in multiparous cows compared with the CON and MB treatments, respectively. Feeding MB + IB increased fat concentration by 0.23 to 0.31 percentage units compared with all other treatments in multiparous cows. Milk yield and dry matter intake (DMI) did not change with treatment. Treatment interacted with week for milk net energy for lactation/DMI; MB + IB tended to increase milk net energy of lactation/DMI by 0.10 Mcal/kg compared with MB and approached a trend for CON, mainly during the early weeks of the treatment period, whereas differences decreased during the last 2 wk of the treatment period. Cows fed MB had the highest 15:0 anteiso fatty acids in the total milk fatty acid profile, which was greater than that for CON or MB + IB cows, but not cows supplemented with isoacids. Cows fed MB alone had the numerically lowest milk net energy for lactation/DMI. The combination of MB + IB appeared optimal for increasing feed efficiency in our study and was not at the expense of average daily gain. Further research is needed for evaluating how potential changes in supplemental isoacid dosage should vary under differing dietary conditions.

Genome-Scale Analysis of the Grapevine KCS Genes Reveals Its Potential Role in Male Sterility.

Very long-chain fatty acid (VLCFA) synthesis in plants, is primarily rate-limited by the enzyme 3-ketoacyl CoA synthase (KCS), which also controls the rate and carbon chain length of VLCFA synthesis. Disruption of VLCFA during pollen development, may affect the pollen wall formation and ultimately lead to male sterility. Our study identified 24 grapevine KCS (VvKCS) genes and provided new names based on their relative chromosome distribution. Based on sequence alignment and phylogenetic investigation, these genes were grouped into seven subgroups, members of the same subgroup having similar motif structures. Synteny analysis of VvKCS genes, showed that the segmental duplication events played an important role in expanding this gene family. Expression profiles obtained from the transcriptome data showed different expression patterns of VvKCS genes in different tissues. Comparison of transcriptome and RT-qPCR data of the male sterile grape 'Y-14' and its fertile parent 'Shine Muscat', revealed that 10 VvKCS genes were significantly differentially expressed at the meiosis stage, which is a critical period of pollen wall formation. Further, joint analysis by weighted gene co-expression network analysis (WGCNA) and Kyoto Encyclopedia of Genes and Genomes (KEGG), revealed that five of these VvKCS (VvKCS6/15/19/20/24) genes were involved in the fatty acid elongation pathway, which may ultimately affect the structural integrity of the pollen wall in 'Y-14'. This systematic analysis provided a foundation for further functional characterization of VvKCS genes, with the aim of grapevine precision breeding improvement.

Expression of fatty acid related gene promotes astaxanthin heterologous production in Chlamydomonas reinhardtii.

Natural astaxanthin is a high-value ketone carotenoid mainly derived from Haematococcus pluvialis, which is an excellent antioxidant for human consumption. To study the role of lipids in accumulation of astaxanthin, the H. pluvialis-derived astaxanthin synthesis pathway genes (β-carotene ketolase gene, BKT and β-carotene hydroxylase gene, BCH) and fatty acid elongation gene (mitochondrial trans-2-enoyl-coa reductase gene, MECR) were heterologously co-expressed in C. reinhardtii. Zeaxanthin, the precursor of astaxanthin synthesis, was significantly increased after BKT and BCH were expressed. In contrast, the α-carotene that competes with astaxanthin synthesis for lycopene decreased significantly. This redistribution of carbon flow was conducive to the synthesis of astaxanthin. In addition, the transformant only expressed astaxanthin metabolism related genes (BKT, BCH) would lead to an increase in total lipid, a decrease in monounsaturated fatty acids and an increase in polyunsaturated fatty acids. On this basis, the expression of MECR gene further increased the total lipid, and the relative content of different fatty acids also changed. The astaxanthin content of algal strains transformed with BKT and BCH genes was nearly 50% higher than that of the wild type. On this basis, the astaxanthin content of transformants expressing MECR gene related to long-chain fatty acid synthesis was increased by 227.5%. In this study, an astaxanthin production model similar to H. pluvialis by combining carotenoid metabolism and fatty acid metabolism was constructed in C. reinhardtii. The results suggest that the increase in astaxanthin is indeed linked to the regulation of fatty acid metabolism, and this link may involve the type of fatty acids and the dynamics of astaxanthin ester in cells. The strategy of promoting the synthesis of fatty acids has potential to achieve efficient production of astaxanthin in C. reinhardtii.

Association of the gut microbiome with kidney function and damage in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

ABSTRACT Background The gut microbiome is altered in chronic kidney disease (CKD), potentially contributing to CKD progression and co-morbidities, but population-based studies of the gut microbiome across a wide range of kidney function and damage are lacking. Methods In the Hispanic Community Health Study/Study of Latinos, gut microbiome was assessed by shotgun sequencing of stool (n = 2,438; 292 with suspected CKD). We examined cross-sectional associations of estimated glomerular filtration rate (eGFR), urinary albumin:creatinine (UAC) ratio, and CKD with gut microbiome features. Kidney trait-related microbiome features were interrogated for correlation with serum metabolites (n = 700), and associations of microbiome-related serum metabolites with kidney trait progression were examined in a prospective analysis (n = 3,635). Results Higher eGFR was associated with overall gut microbiome composition, greater abundance of species from Prevotella, Faecalibacterium, Roseburia, and Eubacterium, and microbial functions related to synthesis of long-chain fatty acids and carbamoyl-phosphate. Higher UAC ratio and CKD were related to lower gut microbiome diversity and altered overall microbiome composition only in participants without diabetes. Microbiome features related to better kidney health were associated with many serum metabolites (e.g., higher indolepropionate, beta-cryptoxanthin; lower imidazole propionate, deoxycholic acids, p-cresol glucuronide). Imidazole propionate, deoxycholic acid metabolites, and p-cresol glucuronide were associated with prospective reductions in eGFR and/or increases in UAC ratio over ~6 y. Conclusions Kidney function is a significant correlate of the gut microbiome, while the relationship of kidney damage with the gut microbiome depends on diabetes status. Gut microbiome metabolites may contribute to CKD progression.

Abstract 24: Association of the Gut Microbiome With Kidney Function and Damage in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

Background: The gut microbiome is altered in chronic kidney disease (CKD), potentially contributing to CKD progression and co-morbidities such as cardiovascular disease, but population-based studies of the gut microbiome across a wide range of kidney function and damage are lacking. Methods: In the Hispanic Community Health Study/Study of Latinos, gut microbiome was assessed by shotgun sequencing of stool (n=2,438; 292 with suspected CKD). We examined cross-sectional associations of estimated glomerular filtration rate (eGFR), urinary albumin:creatinine (UAC) ratio, and CKD with gut microbiome features, adjusting for covariates, and also stratified by diabetes status. Kidney trait-related microbiome features were interrogated for correlation with serum metabolites (n=700), and associations of microbiome-related serum metabolites with kidney trait progression were examined in a prospective analysis (n=3,635) ( Figure 1a ). Results: Higher eGFR was significantly associated with overall gut microbiome composition, greater abundance of species from Prevotella , Faecalibacterium , Roseburia , and Eubacterium , and microbial functions related to synthesis of long-chain fatty acids and carbamoyl-phosphate. Higher UAC ratio and CKD were related to lower gut microbiome diversity and altered overall microbiome composition only in participants without diabetes. Microbiome features related to better kidney health were associated with many serum metabolites (e.g., higher indolepropionate, beta-cryptoxanthin; lower imidazole propionate, deoxycholic acids, p-cresol glucuronide) ( Figure 1b ). Imidazole propionate, deoxycholic acid metabolites, and p-cresol glucuronide were associated with prospective reductions in eGFR and/or increases in the UAC ratio ( Figure 1c ). Conclusions: Kidney function is a significant correlate of the gut microbiome, while the relationship of kidney damage with the gut microbiome depends on diabetes status. Gut microbiome metabolites may contribute to CKD progression.

Transcriptome Profiling Reveals Candidate Genes Related to Stipe Gradient Elongation of Flammulina filiformis.

Stipe gradient elongation is an important and remarkable feature in the development of most mushroom fruiting bodies. However, its molecular mechanism has rarely been described. Here, the decreasing trend of stipe elongation and increasing trend of cell length in a gradient from the top to the base of the stipe were determined in a model basidiomycete mushroom: Flammulina filiformis. According to RNA-seq results, 1409 differentially expressed genes (DEGs) were identified among elongation region (ER), transition region (TR), and stable region (SR) samples, including 26 transcription factors (TFs). Based on Short Time-series Expression Miner (STEM) clustering of DEGs, clusters 1 and 3, with obvious expression trends that were consistent with or in contrast to the elongation rate, were screened. The cluster 1 DEGs were mainly involved in the GO cellular component category and KEGG genetic information processing class; however, the cluster 3 DEGs were mainly involved in metabolic processes. Furthermore, qRT-PCR confirmed that key genes of the long-chain fatty acid synthesis pathway were involved in stipe gradient elongation and regulated by NADPH oxidase-derived ROS signaling molecules. These findings provide an essential basis for understanding the molecular mechanism of stipe gradient elongation.