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Reprogramming of lipid metabolism is emerging as a hallmark of cancer, yet involvement of specific fatty acids (FA) species and related enzymes in tumorigenesis remains unclear. While previous studies have focused on involvement of long‐chain fatty acids (LCFAs) including palmitate in cancer, little attention has been paid to the role of very long‐chain fatty acids (VLCFAs). Here, we show that depletion of acetyl‐CoA carboxylase (ACC1), a critical enzyme involved in the biosynthesis of fatty acids, inhibits both de novo synthesis and elongation of VLCFAs in human cancer cells. ACC1 depletion markedly reduces cellular VLCFA but only marginally influences LCFA levels, including palmitate that can be nutritionally available. Therefore, tumor growth is specifically susceptible to regulation of VLCFAs. We further demonstrate that VLCFA deficiency results in a significant decrease in ceramides as well as downstream glucosylceramides and sphingomyelins, which impairs mitochondrial morphology and renders cancer cells sensitive to oxidative stress and cell death. Taken together, our study highlights that VLCFAs are selectively required for cancer cell survival and reveals a potential strategy to suppress tumor growth. Synopsis: While fatty acids (FA) are established to fuel cellular growth, involvement of specific lipid species in cancerogenesis remains poorly understood. Here, combined genetics and global lipid metabolomics uncover requirement of very long‐chain fatty acids (VLCFAs) and acetyl‐CoA carboxylase (ACC1) for tumor growth, suggesting novel therapeutic avenues. ACC1 depletion reduces VLCFA but not long‐chain fatty acid levels in human cancer cells.VLCFA elongation enhances tumor growth in xenograft models.VLCFA deficiency results in a significant decrease in ceramides as well as downstream glucosylceramides and sphingomyelins.VLCFA deficiency impairs mitochondrial morphology and renders cancer cells sensitive to oxidative stress. [ABSTRACT FROM AUTHOR]

Johnsongrass [Sorghum halepense (L.) Pers.] is a troublesome weed species in different agricultural and non‐agricultural areas. Because of its biology, reproductive system, and seed production, effective management is challenging. An accession with low susceptibility to the acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicides fluazifop‐p‐butyl (fluazifop) and pinoxaden was collected in eastern Arkansas. In this research, the molecular mechanisms responsible for ACCase resistance were investigated. Dose–response experiments showed a resistance factor of 181 and 133 for fluazifop and pinoxaden, respectively. Molecular analysis of both ACCase1 and ACCase2 genes was researched. Nucleotide comparison of ACCase1 between resistant and susceptible accessions showed no single nucleotide polymorphisms. Nonetheless, analysis of ACCase2 in fluazifop‐resistant johnsongrass plants revealed the Ile1781Leu target‐site mutation was dominant (nearly 75%), whereas the majority of pinoxaden‐resistant johnsongrass plants had the Ile2041Asn (60%). Not all sequenced johnsongrass plants displayed a target‐site mutation, suggesting the presence of additional resistance mechanisms. Amplification of ACCase1 and ACCase2 was not responsible for resistance because of the similar values obtained in both resistant and susceptible accessions. Experiments with malathion and NBD‐Cl suggest the presence of herbicide metabolism. Outcomes of this research demonstrated that fluazifop‐ and pinoxaden‐resistant johnsongrass plants displayed a target‐site mutation in ACCase2, but also that non‐target‐site resistance mechanisms would be involved and require a detailed study. [ABSTRACT FROM AUTHOR]

BACKGROUND: Shortawn foxtail (Alopecurus aequalis Sobol.), a competitive grass weed severely infesting overwintering crops worldwide, has evolved resistance to the highly efficient acetyl-CoA carboxylase (ACCase)-inhibiting herbicide fenoxaprop-P-ethyl. The Ile-to-Asn substitution at codon position 2041 of ACCase is a dominant resistance mutation that has been associated with fenoxaprop-P-ethyl resistance in A. aequalis. However, its detection based on conventional methods such as polymerase chain reaction (PCR) and gene sequencing is rather labor- and time-consuming. RESULTS: In order to facilitate its detection in field populations of A. aequalis, a simple and efficient method with high sensitivity to the Ile-2041-Asn mutation was developed based on loop-mediated isothermal amplification (LAMP). A set of four primers was designed to target a 244-bp fragment of ACCase comprising codon position 2041. Using the special primers and genomic DNA of A. aequalis, the concentrations of reaction components, temperature and time each were optimized. The LAMP reaction for the detection of the Ile-2041-Asn mutation was processed at 65 °C for 45 min followed by 80 °C for 10 min to stop the reaction. The LAMP method developed was 1000-fold more sensitive than the conventional PCR method, and the detection was also practicable when using crude DNA of A. aequalis as a template. CONCLUSION: The low cost, simplicity and high sensitivity of the developed LAMP assay make the detection of the Ile-2041-Asn mutation easier and quicker, which may contribute to the monitoring and management of resistance development to fenoxaprop-P-ethyl in A. aequalis. [ABSTRACT FROM AUTHOR]

MicroRNAs are considered to play important roles in cell biological and pathological progress. microRNA‐206 (miR‐206) was reported to participate in lipogenesis, and lipid droplets were necessary for the life cycle of HCV proliferation. Whether miR‐206 was associated with HCV proliferation and the potential mechanism are not clear. In this study, we firstly identified that miR‐206 could inhibit HCV proliferation at the RNA and protein level. Bioinformatical prediction of target genes binding to miR‐206 was performed to investigate whether inhibiting function was due to a lipogenesis pathway. Then, the acetyl‐CoA carboxylase 1 (ACC1) gene was selected as target gene of miR‐206. The dual‐luciferase reporter assay results showed that luciferase significantly decreased in cells transfected with 3′‐UTR of the ACC1 gene and miR‐206. The RNA and protein levels of the ACC1 gene and its pathway genes were significantly lower in cells transfected with miR‐206 than in controls. Furthermore, the lipid droplet numbers also significantly decreased in cells transfected with miR‐206. In conclusion, miR‐206 could inhibit HCV proliferation through depressing ACC1 lipogenesis pathway and decreasing the lipid droplet numbers. miR‐206 might be used as anti‐HCV biochemical drug in the future. [ABSTRACT FROM AUTHOR]

Skeletal muscle training status may influence myofibre regulatory protein signalling in response to contractile activity. The current study employed a purpose-designed ex vivo dynamic contractile protocol to evaluate the effect of exercise-accustomization on canonical myofibre protein signalling for metabolic gene expression and for translation initiation and elongation. To this end, rats completed 8 weeks of in vivo voluntary running training versus no running control intervention, whereupon an ex vivo endurance-type dynamic contraction stimulus was conducted in isolated soleus muscle preparations from both intervention groups. Protein signalling response by phosphorylation was evaluated by immunoblotting at 0 and 3 h following ex vivo stimulation. Phosphorylation of AMP-activated protein kinase a-isoforms and its downstream target, acetyl-CoA carboxylase, as well as phosphorylation of eukaryotic elongation factor 2 (eEF2) was increased immediately following the dynamic contraction protocol (at 0 h). Signalling for translation initiation and elongation was evident at 3 h after dynamic contractile activity, as evidenced by increased phosphorylation of p70 S6 kinase and eukaryotic translation initiation factor 4E-binding protein 1, as well as a decrease in phosphorylation of eEF2 back to resting control levels. However, prior exercise training did not alter phosphorylation responses of the investigated signalling proteins. Accordingly, protein signalling responses to standardized endurance-type contractions may be independent of training status in rat muscle during ex vivo conditions. The present findings add to our current understanding of molecular regulatory events responsible for skeletal muscle plasticity. [ABSTRACT FROM AUTHOR]

There are three pathways for triacylglycerol (TAG) biosynthesis: De novo TAG biosynthesis, phosphatidylcholine‐derived biosynthesis, and cytosolic TAG biosynthesis. Variability in fatty acid composition is mainly associated with phosphatidylcholine‐derived TAG pathway. Mobilization of TAG‐formed through cytosolic pathway into lipid droplets is yet unknown. There are multiple regulatory checkpoints starting from acetyl‐CoA carboxylase to the lipid droplet biogenesis in TAG biosynthesis. Although a primary metabolism, only a few species synthesize oil in seeds for storage, and less than 10 species are commercially exploited. To meet out the growing demand for oil, diversifying into newer sources is the only choice left. The present review highlights the potential strategies targeting species like Azadirachta, Callophyllum, Madhuca, Moringa, Pongamia, Ricinus, and Simarouba, which are not being used for eating but are otherwise high yielding (ranging from 1.5 to 20 tons per hectare) with seeds having a high oil content (40–60%). Additionally, understanding the toxin biosynthesis in Ricinus and Simarouba would be useful in developing toxin‐free oil plants. Realization of the importance of cell cultures as "oil factories" is not too far into the future and would soon be a commercially viable option for producing oils in vitro, round the clock. Highlight: Newer alternative sources like cell cultures and high yielding (nonedible) species with high oil content are commercially viable targets to engineer in producing edible‐grade oil using the omics tool. [ABSTRACT FROM AUTHOR]

Aim: To investigate how subchronic administration of a glucokinase activator (GKA) results in attenuation of the hypoglycaemic effect in the diabetic condition. Materials and Methods: Six‐week‐old db/db mice were fed standard chow containing a GKA or the sodium‐glucose cotransporter 2 inhibitor ipragliflozin for 1, 6, 14 or 28 days. We performed histological evaluation and gene expression analysis of the pancreatic islets and liver after each treatment and compared the results to those in untreated mice. Results: The unsustained hypoglycaemic effect of GKAs was reproduced in db/db mice in conjunction with significant hepatic fat accumulation. The initial reactions to treatment with the GKA in the liver were upregulation of the gene expression of carbohydrate response element‐binding protein beta (Chrebp‐b) and downregulation of phosphoenolpyruvate carboxykinase (Pepck) on day 1. Subsequently, the initial changes in Chrebp‐b and Pepck disappeared and increases in the expression of genes involved in lipogenesis, including acetyl‐CoA carboxylase and fatty acid synthase, were observed. There were no significant changes in the pancreatic β cells nor in hepatic insulin signalling. Conclusions: The GKA showed an unsustained hypoglycaemic effect and promoted hepatic fat accumulation in db/db mice. Dynamic changes in the expression of hepatic genes involved in lipogenesis and gluconeogenesis could affect the unsustained hypoglycaemic effect of the GKA despite no changes in pancreatic β‐cell function and mass. [ABSTRACT FROM AUTHOR]

BACKGROUND Chinese sprangletop (Leptochloa chinensis (L.) Nees) is an invasive grass weed severely infesting rice fields across China. In October 2020, a suspected resistant Leptochloa chinensis population HFFD3 that survived the acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicide cyhalofop‐butyl applied at its field‐recommended rate was collected from a rice field in Feidong County, Anhui Province, China. This study aimed to determine the resistance profile of HFFD3 to ACCase inhibitors and to investigate its mechanisms of resistance to cyhalofop‐butyl. RESULTS: Single‐dose testing confirmed that HFFD3 had evolved resistance to cyhalofop‐butyl. Two loci encoding plastidic ACCase were each amplified from the susceptible (S) and resistant (R, HFFD3) individual plants. Target gene sequencing and derived cleaved amplified polymorphic sequence assay revealed all the R plants carried a Trp‐2027‐Leu substitution in their ACCase1,2 copies. Dose–response bioassays revealed that HFFD3 was highly resistant to cyhalofop‐butyl and exhibited cross‐resistance to metamifop, fenoxaprop‐P‐ethyl, quizalofop‐P‐ethyl, and clethodim. Pre‐treatment with piperonyl butoxide and 4‐chloro‐7‐nitrobenzoxadiazole considerably reversed the resistance of the R plants to cyhalofop‐butyl, by 23% and 43%, respectively. Liquid chromatography–tandem mass spectrometry analysis suggested the metabolic rates of cyhalofop‐butyl were significantly faster in the R than in the S plants. CONCLUSION: This study confirmed the first case of an arable weed species featuring cross‐resistance to ACCase‐inhibiting herbicides due to a novel Trp‐2027‐Leu mutation of ACCase. Target gene mutation and cytochrome P450s‐ and glutathione‐S‐transferases‐involved enhanced metabolism may have simultaneously participated in the resistance of HFFD3 population to cyhalofop‐butyl. [ABSTRACT FROM AUTHOR]

Phosphatidylcholine (PC) is an abundant membrane lipid component in most eukaryotes, including yeast, and has been assigned multiple functions in addition to acting as building block of the lipid bilayer. Here, by isolating S. cerevisiae suppressor mutants that exhibit robust growth in the absence of PC, we show that PC essentiality is subject to cellular evolvability in yeast. The requirement for PC is suppressed by monosomy of chromosome XV or by a point mutation in the ACC1 gene encoding acetyl‐CoA carboxylase. Although these two genetic adaptations rewire lipid biosynthesis in different ways, both decrease Acc1 activity, thereby reducing average acyl chain length. Consistently, soraphen A, a specific inhibitor of Acc1, rescues a yeast mutant with deficient PC synthesis. In the aneuploid suppressor, feedback inhibition of Acc1 through acyl‐CoA produced by fatty acid synthase (FAS) results from upregulation of lipid synthesis. The results show that budding yeast regulates acyl chain length by fine‐tuning the activities of Acc1 and FAS and indicate that PC evolved by benefitting the maintenance of membrane fluidity. SYNOPSIS: Saccharomyces cerevisiae suppressor mutants overcoming choline auxotrophy allow growth in the absence of the major membrane lipid phosphatidylcholine (PC). This study reveals that the interplay between acetyl‐CoA carboxylase (Acc1) and fatty acid synthase (FAS), which regulates lipid acyl chain length, renders PC redundant in such mutant. Most PC‐free choline auxotrophy suppressors are 2n‐1 aneuploids lacking one copy of chromosome XV.Rare diploid suppressor strains contain a homozygous point mutation in the ACC1 gene encoding acetyl‐CoA carboxylase.Aneuploid suppressors rely on feed‐back inhibition of Acc1 by FAS‐derived acyl‐CoA, resulting from up‐regulation of lipid synthesis.Inhibition of Acc1 activity is crucial for suppression by reducing average lipid acyl chain length to maintain membrane fluidity. [ABSTRACT FROM AUTHOR]

Summary: Puberty in female pigs is defined as age at first estrus and gilts that have an earlier age at puberty are more likely to have greater lifetime productivity. Because age at puberty is predictive for sow longevity and lifetime productivity, but not routinely measured in commercial herds, it would be beneficial to use genomic or marker‐assisted selection to improve these traits. A GWAS at the US Meat Animal Research Center (USMARC) identified several loci associated with age at puberty in pigs. Candidate genes in these regions were scanned for potential functional variants using sequence information from the USMARC swine population founder animals and public databases. In total, 135 variants (SNP and insertion/deletions) in 39 genes were genotyped in 1284 phenotyped animals from a validation population sired by Landrace and Yorkshire industry semen using the Agena MassArray system. Twelve variants in eight genes were associated with age at puberty (P < 0.005) with estimated additive SNP effects ranging from 1.6 to 5.3 days. Nine of these variants were non‐synonymous coding changes in AHR, CYP1A2, OR2M4, SDCCAG8, TBC1D1 and ZNF608, two variants were deletions of one and four codons in aryl hydrocarbon receptor, AHR, and the most significant SNP was near an acceptor splice site in the acetyl‐CoA carboxylase alpha, ACACA. Several of the loci identified have a physiological and a genetic role in sexual maturation in humans and other animals and are involved in AHR‐mediated pathways. Further functional validation of these variants could identify causative mutations that influence age at puberty in gilts and possibly sow lifetime productivity. [ABSTRACT FROM AUTHOR]

Biotin protein ligase catalyses the post‐translational modification of biotin carboxyl carrier protein (BCCP) domains, a modification that is crucial for the function of several carboxylases. It is a two‐step process that results in the covalent attachment of biotin to the ϵ‐amino group of a conserved lysine of the BCCP domain of a carboxylase in an ATP‐dependent manner. In Leishmania, three mitochondrial enzymes, acetyl‐CoA carboxylase, methylcrotonyl‐CoA carboxylase and propionyl‐CoA carboxylase, depend on biotinylation for activity. In view of the indispensable role of the biotinylating enzyme in the activation of these carboxylases, crystal structures of L. major biotin protein ligase complexed with biotin and with biotinyl‐5′‐AMP have been solved. L. major biotin protein ligase crystallizes as a unique dimer formed by cross‐handshake interactions of the hinge region of the two monomers formed by partial unfolding of the C‐terminal domain. Interestingly, the substrate (BCCP domain)‐binding site of each monomer is occupied by its own C‐terminal domain in the dimer structure. This was observed in all of the crystals that were obtained, suggesting a closed/inactive conformation of the enzyme. Size‐exclusion chromatography studies carried out using high protein concentrations (0.5 mM) suggest the formation of a concentration‐dependent dimer that exists in equilibrium with the monomer. [ABSTRACT FROM AUTHOR]

Ghrelin and the corticotropin‐releasing factor (CRF) family are known regulators of cellular metabolism and energy balance. We previously demonstrated that myoblast glucose metabolism is regulated by ghrelin and that this effect is mediated by CRF receptor type 2 (CRF‐R2). Here we explored the effect of des‐acyl ghrelin, the major circulating isoform of ghrelin, on cellular metabolism in mouse myoblast C2C12 cells, and examined whether CRF family receptors mediate its metabolic effects in muscle cells. C2C12 cells were exposed to des‐acyl ghrelin with or without the CRF‐R1‐ and CRF‐R2‐specific antagonists antalarmin or antisauvagine‐30, respectively. Des‐acyl ghrelin reduced glucose uptake and expression of the glucose transporter GLUT4, but induced retinol‐binding protein 4 (RBP4) expression. Antalarmin and antisauvagine‐30 inhibited the induction of glucose uptake by des‐acyl ghrelin and its effect on GLUT4 and RBP4 expression. Moreover, treating C2C12 cells with des‐acyl ghrelin resulted in cAMP activation in response to the CRF‐R1‐specific ligand stressin, and the CRF‐R2‐specific ligand Ucn3. Furthermore, des‐acyl ghrelin reduced the expression of uncoupling proteins UCP2 and UCP3. Adding antalarmin or antisauvagine‐30 to the medium reversed this effect. Finally, des‐acyl ghrelin elevated lipid content and acetyl‐CoA carboxylase expression in C2C12 cells. Our results suggest that during food deprivation, des‐acyl ghrelin signals the muscle cells that glucose levels are low and that they should switch to fatty acids for their metabolic fuel. [ABSTRACT FROM AUTHOR]

Ghrelin and the corticotropin‐releasing factor (CRF) family are known regulators of cellular metabolism and energy balance. We previously demonstrated that myoblast glucose metabolism is regulated by ghrelin and that this effect is mediated by CRF receptor type 2 (CRF‐R2). Here we explored the effect of des‐acyl ghrelin, the major circulating isoform of ghrelin, on cellular metabolism in mouse myoblast C2C12 cells, and examined whether CRF family receptors mediate its metabolic effects in muscle cells. C2C12 cells were exposed to des‐acyl ghrelin with or without the CRF‐R1‐ and CRF‐R2‐specific antagonists antalarmin or antisauvagine‐30, respectively. Des‐acyl ghrelin reduced glucose uptake and expression of the glucose transporter GLUT4, but induced retinol‐binding protein 4 (RBP4) expression. Antalarmin and antisauvagine‐30 inhibited the induction of glucose uptake by des‐acyl ghrelin and its effect on GLUT4 and RBP4 expression. Moreover, treating C2C12 cells with des‐acyl ghrelin resulted in cAMP activation in response to the CRF‐R1‐specific ligand stressin, and the CRF‐R2‐specific ligand Ucn3. Furthermore, des‐acyl ghrelin reduced the expression of uncoupling proteins UCP2 and UCP3. Adding antalarmin or antisauvagine‐30 to the medium reversed this effect. Finally, des‐acyl ghrelin elevated lipid content and acetyl‐CoA carboxylase expression in C2C12 cells. Our results suggest that during food deprivation, des‐acyl ghrelin signals the muscle cells that glucose levels are low and that they should switch to fatty acids for their metabolic fuel. [ABSTRACT FROM AUTHOR]

BACKGROUND: Crop protection solutions for the control of key economic sucking pests derive essentially from neuronal and muscular acting chemistries, wherein neonicotinoid uses largely dominated for the last two decades. Anticipating likely resistance development of some of those arthropod species to this particular class, we intensified research activities on a non‐neuronal site of action targeting insect growth and development some 10 years ago. RESULTS: Our innovation path featured reactivation of a scarcely used and simple building block from the 1960s, namely N‐methoxy‐4‐piperidone 3. Its judicious incorporation into the 2‐aryl‐1,3‐dione scaffold of IRAC group 23 inhibitors of fatty acid biosynthesis resulted in novel tetramic acid derivatives acting on acetyl‐coenzyme A carboxylase (ACCase). The optimization campaign focused on modulation of the aryl substitution pattern and understanding substituent options at the lactam nitrogen position of those spiroheterocyclic pyrrolidine‐dione derivatives towards an effective control of sucking insects and mites. This work gratifyingly culminated in the discovery of spiro N‐methoxy piperidine containing proinsecticide spiropidion 1. Following in planta release, its insecticidally active dione metabolite 2 is translaminar and two‐way systemic (both xylem and phloem mobile) for a full plant protection against arthropod pests. CONCLUSION: Owing to such unique plant systemic properties, growing shoots and roots actually not directly exposed to spiropidion‐based chemistry after foliar application nevertheless benefit from its long‐lasting efficacy. Spiropidion is for use in field crops, speciality crops and vegetables controlling a broad range of sucking pests. In light of other performance and safety profiles of spiropidion, an IPM fit may be expected. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background and Purpose: Non-alcoholic fatty liver disease (NAFLD), including non-alcoholic steatohepatitis, is closely related to metabolic diseases such as obesity and diabetes. Despite an accumulating number of studies, no pharmacotherapy that targets NAFLD has received general approval for clinical use.Experimental Approach: Inhibition of the sodium-glucose cotransporter 2 (SGLT2) is a promising approach to treat diabetes, obesity, and associated metabolic disorders. In this study, we investigated the effect of a novel SGLT2 inhibitor, NGI001, on NAFLD and obesity-associated metabolic symptoms in high-fat diet (HFD)-induced obese mice.Key Results: Delayed intervention with NGI001 protected against body weight gain, hyperglycaemia, hyperlipidaemia, and hyperinsulinaemia, compared with HFD alone. Adipocyte hypertrophy was prevented by administering NGI001. NGI001 inhibited impaired glucose metabolism and regulated the secretion of adipokines associated with insulin resistance. In addition, NGI001 supplementation suppressed hepatic lipid accumulation and inflammation but had little effect on kidney function. In-depth investigations showed that NGI001 ameliorated fat deposition and increased AMPK phosphorylation, resulting in phosphorylation of its major downstream target, acetyl-CoA carboxylase, in human hepatocyte HuS-E/2 cells. This cascade ultimately led to the down-regulation of downstream fatty acid synthesis-related molecules and the up-regulation of downstream β oxidation-associated molecules. Surprisingly, NGI001 decreased gene and protein expression of SGLT1 and SGLT2 and glucose uptake in oleic acid-treated HuS-E/2 cells.Conclusion and Implications: Our findings suggest the novel SGLT2 inhibitor, NGI001 has therapeutic potential to attenuate or delay the onset of diet-induced metabolic diseases and NAFLD. [ABSTRACT FROM AUTHOR]

BACKGROUND Asia minor bluegrass (Polypogon fugax Nees ex Steud.) is an invasive grass species severely infesting wheat and canola fields in China. In May 2017, a suspected resistant P. fugax population AHHY that survived fenoxaprop‐P‐ethyl applied at its field‐recommended rate was collected from a wheat field in Huaiyuan County, Anhui Province, China. This study aimed to determine the resistance profile of AHHY to acetyl‐CoA carboxylase (ACCase) inhibitors and to investigate its mechanisms of resistance to fenoxaprop. RESULTS: Single‐dose testing indicated that the AHHY population had evolved resistance to fenoxaprop. The partial carboxyltransferase domain of ACCase in P. fugax was amplified and compared. Four loci encoding plastidic ACCase were isolated from both the resistant and sensitive individuals. Combining gene sequencing with the derived cleaved amplified polymorphic sequence assay, we found that 100% of the plants of AHHY carried Trp‐1999‐Ser mutation in their ACCase1,1–2 allele. Whole‐plant dose–response bioassay indicated that AHHY was highly resistant to fenoxaprop and pinoxaden (resistance index (RI) ≥ 10) with low resistance to clodinafop‐propargyl, sethoxydim, and clethodim (2 ≤ RI < 5). Pre‐treatment with piperonyl butoxide largely reduced (55%) the weed's resistance to fenoxaprop. Both basal and fenoxaprop‐induced glutathione S‐transferases activities toward 1‐chloro‐2, 4‐dinitrobenzene were significantly higher in resistant plants than in susceptible plants. CONCLUSION: This study revealed that P. fugax had multiple alleles encoding plastidic ACCase, and reported for the first time the occurrence of Trp‐1999‐Ser mutation and non‐target‐site resistance in this species. Fenoxaprop resistance in AHHY plants was conferred by target‐site mutation and P450s‐involved enhanced metabolism. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: A field‐evolved herbicide‐resistant weed population can represent a heterogeneous composite of subpopulations that differ in their susceptibility and responsiveness to herbicide hormesis. Variable hormesis responsiveness can result in selection for and against certain subpopulations under low herbicide doses, and this has the potential to contribute to the evolution of resistance. The relevance of this hypothesis at practical field rates was studied for two field‐collected acetyl‐coenzyme A carboxylase (ACCase) target‐site resistant (TSR) biotypes of Alopecurus myosuroides Huds. (haplotype Leu1781) exposed to three ACCase inhibitors. Herbicide dose responses were evaluated at the population level and at different subpopulation levels after the dissection of individual plants by herbicide selection and genotyping. RESULTS: The practical field rates of fenoxaprop‐P were lower than the observed hormetic doses in the resistant subpopulation, whereas the field rates of clodinafop and cycloxydim stimulated the shoot biomass in different resistant subpopulations by 21–38% above that of the control. Because variable dose levels induced hormesis in the different subpopulations, the practical field rates showed a significant potential to selectively enhance parts of a resistant field population, but did not impact or adversely affect other parts of the population. CONCLUSION: As a consequence of population heterogeneity, herbicide hormesis may impact resistance evolution in weeds at realistic use rates via the selective promotion of individual genotypes. However, the practical relevance of this phenomenon may be influenced by many factors, such as the herbicidal active ingredient used, as indicated in this study. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Alopecurus japonicus is a serious grass weed species in wheat fields in eastern Asia, and has evolved strong resistance to acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicides. Although target‐site resistance (TSR) to ACCase inhibitors in A. japonicus has been reported, non‐target site resistance (NTSR) has not. This study investigated both TSR and NTSR in a fenoxaprop‐P‐ethyl‐resistant A. japonicus population (AHFD‐3), which was collected in Feidong County, Anhui Province, China. RESULTS: We found that AHFD‐3 exhibited high resistance to fenoxaprop‐P‐ethyl and low resistance to flucarbazone‐sodium. The sensitivity of AHFD‐3 to fenoxaprop‐P‐ethyl increased significantly after treatment with cytochrome P450 (P450) inhibitors; however, such synergies between P450 inhibitors and fenoxaprop‐P‐ethyl were not found in two control populations. Sequences of the entire carboxyltransferase domain of A. japonicus ACCase were obtained, and AHFD‐3 plants showed an Asp‐2078‐Gly substitution in the ACCase. With the derived cleaved amplified polymorphic sequence (dCAPS) method, we found that 85.4% of the plants of AHFD‐3 carried this mutation. The P450 content in AHFD‐3 plants was significantly higher than those of the two control populations after treatment with fenoxaprop‐P‐ethyl. Ten partial sequences of P450 genes in A. japonicus were cloned. Three P450 genes were up‐regulated 12 h after fenoxaprop‐P‐ethyl treatment, which were all from the P450 subfamily CYP72A. Moreover, a P450 gene from the P450 family CYP81 was up‐regulated after fenoxaprop‐P‐ethyl treatment in all populations studied. CONCLUSION: Fenoxaprop‐P‐ethyl resistance in AHFD‐3 plants was conferred by up‐regulation of cytochrome P450s in the CYP72A subfamily and target site mutation of the ACCase gene. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

We have studied a series of human acetyl‐CoA carboxylase (ACC) 1 and ACC2 proteins with deletions and/or Ser to Ala substitutions of the known phosphorylation sites. In vitro dephosphorylation/phosphorylation experiments reveal a substantial level of phosphorylation of human ACCs produced in insect cells. Our results are consistent with AMPK phosphorylation of Ser29, Ser80, Ser1,201, and Ser1,216. Phosphorylation of the N‐terminal regulatory domain decreases ACC1 activity, while phosphorylation of residues in the ACC central domain has no effect. Inhibition of the activity by phosphorylation is significantly more profound at citrate concentrations below 2 m m. Furthermore, deletion of the N‐terminal domain facilitates structural changes induced by citrate, including conversion of ACC dimers to linear polymers. We have also identified ACC2 amino acid mutations affecting specific inhibition of the isozyme by compound CD‐017‐0191. They form two clusters separated by 60–90 Å: one located in the vicinity of the BC active site and the other one in the vicinity of the ACC1 phosphorylation sites in the central domain, suggesting a contribution of the interface of two ACC dimers in the polymer to the inhibitor binding site. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Glyphosate, paraquat and acetyl CoA carboxylase (ACCase)‐inhibiting herbicides are widely used in California annual and perennial cropping systems. Recently, glyphosate, paraquat, and ACCase‐ and acetolactate synthase (ALS)‐inhibitor resistance was confirmed in several Italian ryegrass populations from the Central Valley of California. This research characterized the possible mechanisms of resistance. RESULTS: Multiple‐resistant populations (MR1, MR2) are resistant to several herbicides from at least three modes of action. Dose–response experiments revealed that the MR1 population was 45.9‐, 122.7‐ and 20.5‐fold, and the MR2 population was 24.8‐, 93.9‐ and 4.0‐fold less susceptible to glyphosate, sethoxydim and paraquat, respectively, than the susceptible (Sus) population. Accumulation of shikimate in Sus plants was significantly greater than in MR plants 32 h after light pretreatments. Glyphosate resistance in MR plants was at least partially due to Pro106‐to‐Ala and Pro106‐to‐Thr substitutions at site 106 of 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS). EPSPS gene copy number and expression level were similar in plants from the Sus and MR populations. An Ile1781‐to‐Leu substitution in ACCase gene of MR plants conferred a high level of resistance to sethoxydim and cross‐resistance to other ACCase‐inhibitors. Radiolabeled herbicide studies and phosphorimaging indicated that MR plants had restricted translocation of 14C‐paraquat to untreated leaves compared to Sus plants. CONCLUSION: This study shows that multiple herbicide resistance in Italian ryegrass populations in California, USA, is due to both target‐site and non‐target‐site resistance mechanisms. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Haloxyfop- R-methyl is a widely used herbicide to control Poaceae weeds. Alopecurus japonicus, a widespread annual grass, can no longer be controlled by haloxyfop- R-methyl after continuous use of this herbicide for several years. RESULTS: Dose-response experiments have established that the Js-R biotype of A. japonicas has evolved resistance to aryloxyphenoxypropionates (APPs). Target-site enzyme sensitivity experiments have established that the haloxyfop (free acid) rate causing 50% inhibition of acetyl-CoA carboxylase (ACCase) activity (I50) for the resistant (Js-R) biotype is 11 times higher than that for the susceptible (Js-S) biotype. In many cases, resistance to ACCase-inhibiting herbicides is due to a resistant ACCase enzyme. Full-length DNA and mRNA sequences of the plastidic ACCase gene were amplified. Eight single-nucleotide differences were detected in this region. Four of the nucleotide changes were silent mutations. However, the other four nucleotide mutations caused four amino acid substitutions, replacing Arg-1734 with Gly, Met-1738 with Leu, Thr-1739 with Ser and Ile-2041 with Asn in the R biotype respectively; the substitution at position 2041 had been reported, while the other three had not. CONCLUSION: The ACCase in the Js-R biotype was less susceptible to haloxyfop- R-methyl than that in the Js-S biotype. Moreover, the amino acid substitution of Ile-2041 with Asn might confer resistance to haloxyfop- R-methyl in A. japonicas. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Caffeine activates 5′AMP-activated protein kinase (AMPK), a signalling intermediary implicated in the regulation of glucose, lipid and energy metabolism in skeletal muscle. Skeletal muscle expresses two catalytic α subunits of AMPK, α1 and α2, but the isoform specificity of caffeine-induced AMPK activation is unclear. The aim of this study was to determine which α isoform is preferentially activated by caffeine in vitro and in vivo using rat skeletal muscle. Rat epitrochlearis muscle was isolated and incubated in vitro in the absence or presence of caffeine. In another experiment, the muscle was dissected after intravenous injection of caffeine. Isoform-specific AMPK activity, the phosphorylation status of AMPKα Thr and acetyl-CoA carboxylase (ACC) Ser, the concentrations of ATP, phosphocreatine (PCr) and glycogen, and 3- O-methyl--glucose (3MG) transport activity were estimated. Incubation of isolated epitrochlearis muscle with 1 m of caffeine for 15 min increased AMPKα1 activity, but not AMPKα2 activity; concentrations of ATP, PCr and glycogen were not affected. Incubation with 3 m of caffeine activated AMPKα2 and reduced PCr and glycogen concentrations. Incubation with 1 m of caffeine increased the phosphorylation of AMPK and ACC and enhanced 3MG transport. Intravenous injection of caffeine (5 mg kg) predominantly activated AMPKα1 and increased 3MG transport without affecting energy status. Our results suggest that of the two α isoforms of AMPK, AMPKα1 is predominantly activated by caffeine via an energy-independent mechanism and that the activation of AMPKα1 increases glucose transport and ACC phosphorylation in skeletal muscle. [ABSTRACT FROM AUTHOR]

While the brain does not utilize fatty acids as a primary energy source, recent evidence shows that intermediates of fatty acid metabolism serve as hypothalamic sensors of energy status. Increased hypothalamic malonyl-CoA, an intermediate in fatty acid synthesis, is indicative of energy surplus and leads to the suppression of food intake and increased energy expenditure. Malonyl-CoA functions as an inhibitor of carnitine palmitoyl-transferase 1 (CPT1), a mitochondrial outer membrane enzyme that initiates translocation of fatty acids into mitochondria for oxidation. The mammalian brain expresses a unique homologous CPT1, CPT1c, that binds malonyl-CoA tightly but does not support fatty acid oxidation in vivo, in hypothalamic explants or in heterologous cell culture systems. CPT1c knockout (KO) mice under fasted or refed conditions do not exhibit an altered CNS transcriptome of genes known to be involved in fatty acid metabolism. CPT1c KO mice exhibit normal levels of metabolites and of hypothalamic malonyl-CoA and fatty acyl-CoA levels either in the fasted or refed states. However, CPT1c KO mice exhibit decreased food intake and lower body weight than wild-type littermates. In contrast, CPT1c KO mice gain excessive body weight and body fat when fed a high-fat diet while maintaining lower or equivalent food intake. Heterozygous mice display an intermediate phenotype. These findings provide further evidence that CPT1c plays a role in maintaining energy homeostasis, but not through altered fatty acid oxidation. [ABSTRACT FROM AUTHOR]

We assessed the contributions of target site- and non-target site-based resistance to herbicides inhibiting acetyl-coenzyme A carboxylase (ACC) in Alopecurus myosuroides (black grass). A total of 243 A. myosuroides populations collected across France were analysed using herbicide sensitivity bioassay (24 300 seedlings analysed) and ACC genotyping (13 188 seedlings analysed). Seedlings resistant to at least one ACC-inhibiting herbicide were detected in 99.2% of the populations. Mutant, resistant ACC allele(s) were detected in 56.8% of the populations. Among the five resistant ACC alleles known in A. myosuroides, alleles containing an isoleucine-to-leucine substitution at codon 1781 were predominant (59.5% of the plants containing resistant ACC alleles). Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 75% of the plants resistant to ACC-inhibiting herbicides in France would be resistant via increased herbicide metabolism. Analysis of herbicide application records suggested that in 15.9% of the populations studied, metabolism-based resistance to ACC-inhibiting herbicides was mostly selected for by herbicides with other modes of action. Our study revealed the importance of non-target site-based resistance in A. myosuroides. Using herbicides with alternative modes of action to control populations resistant to ACC-inhibiting herbicides, the recommended management approach, may thus be jeopardised by the widespread occurrence of metabolism-based resistance mechanisms conferring broad-spectrum cross-resistance. [ABSTRACT FROM AUTHOR]

• Effective herbicide resistance management requires an assessment of the range of spatial dispersion of resistance genes among weed populations and identification of the vectors of this dispersion. • In the grass weed Alopecurus myosuroides (black-grass), seven alleles of the acetyl-CoA carboxylase ( ACCase) gene are known to confer herbicide resistance. Here, we assessed their respective frequencies and spatial distribution on two nested geographical scales (the whole of France and the French administrative district of Côte d’Or) by genotyping 13 151 plants originating from 243 fields. • Genetic variation in ACCase was structured in local populations at both geographical scales. No spatial structure in the distribution of resistant ACCase alleles and no isolation by distance were detected at either geographical scale investigated. • These data, together with ACCase sequencing and data from the literature, suggest that evolution of A. myosuroides resistance to herbicides occurred at the level of the field or group of adjacent fields by multiple, independent appearances of mutant ACCase alleles that seem to have rather restricted spatial propagation. Seed transportation by farm machinery seems the most likely vector for resistance gene dispersal in A. myosuroides. [ABSTRACT FROM AUTHOR]

Resistance to the cyclohexanedione (CHD) herbicide sethoxydim was investigated in two UK Lolium multiflorum populations, Yorks A2 and PYL. Resistance screening experiments demonstrated a qualitative difference in the responses of the two populations to sethoxydim, suggesting that the molecular basis of resistance between them was different. After treatment, Yorks A2 plants were either alive (78% of sample tested) or dead (22% tested) but plants of the PYL population showed two further intermediate categories of response. The level of acetyl-CoA carboxylase (ACCase) insensitivity directly correlated with the degree of resistance at the whole plant level, indicating that the molecular basis of resistance is associated with differences in ACCase sensitivity in each population. Direct sequencing of the carboxyl transferase domain of the ACCase gene showed that an Ile-418-Leu substitution in the L. multiflorum chloroplastic ACCase (GenBank accession number ) confers resistance to sethoxydim in Yorks A2. This corresponds to amino acid residue 1781 in the Alopecurus myosuroides full ACCase sequence. This is the first report of this mutation in this L. multiflorum, which has also been reported in four other grass-weeds, including L. rigidum. However, no amino acid substitutions were found to be specifically associated with the resistant phenotypes in the PYL population and the molecular basis of resistance in this population remains to be resolved. [ABSTRACT FROM AUTHOR]

Two species of diatoms were genetically transformed by introducing plasmid vectors containing the Escherichia coli neomycin phosphotransferase II (nptII) gene. Expression of the bacterial nptII gene in the diatoms was achieved using the putative promoter and terminator sequences from the acetyl-CoA carboxylase gene from the centric diatom Cyclotella cryptica T13L Reimann, Lewin, and Guillard. The vectors were introduced into C. cryptica and the pennate diatom Navicula saprophila NAVIC1 Lange-Bertalot and Bonik by microprojectile bombardment. Putative transformants were selected based on their ability to grow in the presence of the antibiotic G418, and production of the neomycin phosphotransferase protein by the transformed cells was confirmed by western blotting. The foreign DNA integrated into one or more random sites within the genome of the transformed algal cells, often in the form of tandem repeats. This is the first report of reproducible, stable genetic transformation of a chlorophyll c-containing alga. [ABSTRACT FROM AUTHOR]