HSQC-TOCSY Fingerprinting for Prioritization of Polyketide- and Peptide-Producing Microbial Isolates.

PubMed

Buedenbender, Larissa; Habener, Leesa J; Grkovic, Tanja; Kurtböke, D İpek; Duffy, Sandra; Avery, Vicky M; Carroll, Anthony R

2018-04-27

Microbial products are a promising source for drug leads as a result of their unique structural diversity. However, reisolation of already known natural products significantly hampers the discovery process, and it is therefore important to incorporate effective microbial isolate selection and dereplication protocols early in microbial natural product studies. We have developed a systematic approach for prioritization of microbial isolates for natural product discovery based on heteronuclear single-quantum correlation-total correlation spectroscopy (HSQC-TOCSY) nuclear magnetic resonance profiles in combination with antiplasmodial activity of extracts. The HSQC-TOCSY experiments allowed for unfractionated microbial extracts containing polyketide and peptidic natural products to be rapidly identified. Here, we highlight how this approach was used to prioritize extracts derived from a library of 119 ascidian-associated actinomycetes that possess a higher potential to produce bioactive polyketides and peptides.

Bio-based production of fuels and industrial chemicals by repurposing antibiotic-producing type I modular polyketide synthases: opportunities and challenges.

PubMed

Yuzawa, Satoshi; Keasling, Jay D; Katz, Leonard

2017-04-01

Complex polyketides comprise a large number of natural products that have broad application in medicine and agriculture. They are produced in bacteria and fungi from large enzyme complexes named type I modular polyketide synthases (PKSs) that are composed of multifunctional polypeptides containing discrete enzymatic domains organized into modules. The modular nature of PKSs has enabled a multitude of efforts to engineer the PKS genes to produce novel polyketides of predicted structure. We have repurposed PKSs to produce a number of short-chain mono- and di-carboxylic acids and ketones that could have applications as fuels or industrial chemicals.

The Structural Enzymology of Iterative Aromatic Polyketide Synthases: A Critical Comparison with Fatty Acid Synthases.

PubMed

Tsai, Shiou-Chuan Sheryl

2018-06-20

Polyketides are a large family of structurally complex natural products including compounds with important bioactivities. Polyketides are biosynthesized by polyketide synthases (PKSs), multienzyme complexes derived evolutionarily from fatty acid synthases (FASs). The focus of this review is to critically compare the properties of FASs with iterative aromatic PKSs, including type II PKSs and fungal type I nonreducing PKSs whose chemical logic is distinct from that of modular PKSs. This review focuses on structural and enzymological studies that reveal both similarities and striking differences between FASs and aromatic PKSs. The potential application of FAS and aromatic PKS structures for bioengineering future drugs and biofuels is highlighted.

Producing biofuels using polyketide synthases

DOEpatents

Katz, Leonard; Fortman, Jeffrey L; Keasling, Jay D

2013-04-16

The present invention provides for a non-naturally occurring polyketide synthase (PKS) capable of synthesizing a carboxylic acid or a lactone, and a composition such that a carboxylic acid or lactone is included. The carboxylic acid or lactone, or derivative thereof, is useful as a biofuel. The present invention also provides for a recombinant nucleic acid or vector that encodes such a PKS, and host cells which also have such a recombinant nucleic acid or vector. The present invention also provides for a method of producing such carboxylic acids or lactones using such a PKS.

A "methyl extension" strategy for polyketide natural product linker site validation and its application to dictyostatin.

PubMed

Ho, Stephen; Sackett, Dan L; Leighton, James L

2015-11-11

An approach to the validation of linker strategies for polyketide natural products with few or no obvious handles for linker attachment, and its application to dictyostatin, are described. Analogues in which the C(6)- and C(12)-methyl groups were replaced by 4-azidobutyl groups were prepared and shown to retain the low nanomolar potency of dictyostatin. Further, conjugation of the C(6) analogue with a cyclooctyne resulted in only minor attenuations in potency. Together, these results shed light on the binding of dictyostatin to β-tubulin, establish a validated linker strategy for dictyostatin, and set the stage for the synthesis and study of dictyostatin conjugates.

Expression, purification and crystallization of a plant polyketide cyclase from Cannabis sativa

PubMed Central

Yang, Xinmei; Matsui, Takashi; Mori, Takahiro; Taura, Futoshi; Noguchi, Hiroshi; Abe, Ikuro; Morita, Hiroyuki

2015-01-01

Plant polyketides are a structurally diverse family of natural products. In the biosynthesis of plant polyketides, the construction of the carbocyclic scaffold is a key step in diversifying the polyketide structure. Olivetolic acid cyclase (OAC) from Cannabis sativa L. is the only known plant polyketide cyclase that catalyzes the C2–C7 intramolecular aldol cyclization of linear pentyl tetra-β-ketide-CoA to generate olivetolic acid in the biosynthesis of cannabinoids. The enzyme is also thought to belong to the dimeric α+β barrel (DABB) protein family. However, because of a lack of functional analysis of other plant DABB proteins and low sequence identity with the functionally distinct bacterial DABB proteins, the catalytic mechanism of OAC has remained unclear. To clarify the intimate catalytic mechanism of OAC, the enzyme was overexpressed in Escherichia coli and crystallized using the vapour-diffusion method. The crystals diffracted X-rays to 1.40 Å resolution and belonged to space group P3121 or P3221, with unit-cell parameters a = b = 47.3, c = 176.0 Å. Further crystallographic analysis will provide valuable insights into the structure–function relationship and catalytic mechanism of OAC. PMID:26625288

Expression, purification and crystallization of a plant polyketide cyclase from Cannabis sativa.

PubMed

Yang, Xinmei; Matsui, Takashi; Mori, Takahiro; Taura, Futoshi; Noguchi, Hiroshi; Abe, Ikuro; Morita, Hiroyuki

2015-12-01

Plant polyketides are a structurally diverse family of natural products. In the biosynthesis of plant polyketides, the construction of the carbocyclic scaffold is a key step in diversifying the polyketide structure. Olivetolic acid cyclase (OAC) from Cannabis sativa L. is the only known plant polyketide cyclase that catalyzes the C2-C7 intramolecular aldol cyclization of linear pentyl tetra-β-ketide-CoA to generate olivetolic acid in the biosynthesis of cannabinoids. The enzyme is also thought to belong to the dimeric α+β barrel (DABB) protein family. However, because of a lack of functional analysis of other plant DABB proteins and low sequence identity with the functionally distinct bacterial DABB proteins, the catalytic mechanism of OAC has remained unclear. To clarify the intimate catalytic mechanism of OAC, the enzyme was overexpressed in Escherichia coli and crystallized using the vapour-diffusion method. The crystals diffracted X-rays to 1.40 Å resolution and belonged to space group P3121 or P3221, with unit-cell parameters a = b = 47.3, c = 176.0 Å. Further crystallographic analysis will provide valuable insights into the structure-function relationship and catalytic mechanism of OAC.

Antimicrobial polyketide furanoterpenoids from seaweed-associated heterotrophic bacterium Bacillus subtilis MTCC 10403.

PubMed

Chakraborty, Kajal; Thilakan, Bini; Raola, Vamshi Krishna

2017-10-01

Brown seaweed Anthophycus longifolius (Turner) Kützing (family Sargassaceae) associated heterotrophic bacterium Bacillus subtilis MTCC 10403 was found to be a potent isolate with broad range of antibacterial activity against important perceptive food pathogens Vibrio parahaemolyticus, V. vulnificus, and Aeromonas hydrophila. This bacterium was positive for polyketide synthetase gene (KC589397), and therefore, was selected to bioprospect specialized metabolites bearing polyketide backbone. Bioactivity-guided chromatographic fractionation of the ethyl acetate extract of the seaweed-associated bacterium segregated four homologous polyketide furanoterpenoids with potential antibacterial activities against clinically important pathogens. The minimum inhibitory concentration (MIC) assay showed that the referral antibiotics tetracycline and ampicillin were active at 25 μg/mL against the test pathogens, whereas the previously undescribed (4E)-methyl 13-((16-(furan-2-yl) ethyl)-octahydro-7-hydroxy-4-((E)-23-methylbut-21-enyl)-2H-chromen-6-yl)-4-methylpent-4-enoate (compound 1) and methyl 3-(hexahydro-9-((E)-3-methylpent-1-enyl)-4H-furo[3,2-g]isochromen-6-yl) propanoate (compound 3) displayed antibacterial activities against the test pathogens at a lesser concentration (MIC < 7 μg/mL). The title compounds were characterized by comprehensive nuclear magnetic resonance and mass spectroscopic experiments. Polyketide synthase catalyzed putative biosynthetic mechanism additionally corroborated the structural ascriptions of the hitherto undescribed furanoterpenoids from seaweed-associated bacterial symbiont. The electronic and hydrophobic parameters appeared to hold a conspicuous part in directing the antibacterial properties of the compounds. Seaweed-associated B. subtilis MTCC 10403 demonstrated to represent a potential source of antimicrobial polyketides for pharmaceutical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polyketides, toxins and pigments in Penicillium marneffei.

PubMed

Tam, Emily W T; Tsang, Chi-Ching; Lau, Susanna K P; Woo, Patrick C Y

2015-10-30

Penicillium marneffei (synonym: Talaromyces marneffei) is the most important pathogenic thermally dimorphic fungus in China and Southeastern Asia. The HIV/AIDS pandemic, particularly in China and other Southeast Asian countries, has led to the emergence of P. marneffei infection as an important AIDS-defining condition. Recently, we published the genome sequence of P. marneffei. In the P. marneffei genome, 23 polyketide synthase genes and two polyketide synthase-non-ribosomal peptide synthase hybrid genes were identified. This number is much higher than those of Coccidioides immitis and Histoplasma capsulatum, important pathogenic thermally dimorphic fungi in the Western world. Phylogenetically, these polyketide synthase genes were distributed evenly with their counterparts found in Aspergillus species and other fungi, suggesting that polyketide synthases in P. marneffei did not diverge from lineage-specific gene duplication through a recent expansion. Gene knockdown experiments and ultra-high performance liquid chromatography-photodiode array detector/electrospray ionization-quadruple time of flight-mass spectrometry analysis confirmed that at least four of the polyketide synthase genes were involved in the biosynthesis of various pigments in P. marneffei, including melanin, mitorubrinic acid, mitorubrinol, monascorubrin, rubropunctatin, citrinin and ankaflavin, some of which were mycotoxins and virulence factors of the fungus.

Chemical Probes for the Functionalization of Polyketide Intermediates**

PubMed Central

Riva, Elena; Wilkening, Ina; Gazzola, Silvia; Li, W M Ariel; Smith, Luke; Leadlay, Peter F; Tosin, Manuela

2014-01-01

A library of functionalized chemical probes capable of reacting with ketosynthase-bound biosynthetic intermediates was prepared and utilized to explore in vivo polyketide diversification. Fermentation of ACP mutants of S. lasaliensis in the presence of the probes generated a range of unnatural polyketide derivatives, including novel putative lasalocid A derivatives characterized by variable aryl ketone moieties and linear polyketide chains (bearing alkyne/azide handles and fluorine) flanking the polyether scaffold. By providing direct information on microorganism tolerance and enzyme processing of unnatural malonyl-ACP analogues, as well as on the amenability of unnatural polyketides to further structural modifications, the chemical probes constitute invaluable tools for the development of novel mutasynthesis and synthetic biology. PMID:25212788

A proteomic survey of nonribosomal peptide and polyketide biosynthesis in actinobacteria

USDA-ARS?s Scientific Manuscript database

Actinobacteria such as streptomycetes are renowned for their ability to produce bioactive natural products including nonribosomal peptides (NRPs) and polyketides (PKs). The advent of genome sequencing has revealed an even larger genetic repertoire for secondary metabolism with most of the small mole...

Engineered fungal polyketide biosynthesis in Pichia pastoris: a potential excellent host for polyketide production

PubMed Central

2013-01-01

Background Polyketides are one of the most important classes of secondary metabolites and usually make good drugs. Currently, heterologous production of fungal polyketides for developing a high potential industrial application system with high production capacity and pharmacutical feasibility was still at its infancy. Pichia pastoris is a highly successful system for the high production of a variety of heterologous proteins. In this work, we aim to develop a P. pastoris based in vivo fungal polyketide production system for first time and evaluate its feasibility for future industrial application. Results A recombinant P. pastoris GS115-NpgA-ATX with Aspergillus nidulans phosphopantetheinyl transferase (PPtase) gene npgA and Aspergillus terrus 6-methylsalicylic acid (6-MSA) synthase (6-MSAS) gene atX was constructed. A specific compound was isolated and idenified as 6-MSA by HPLC, LC-MS and NMR. Transcription of both genes were detected. In 5-L bioreactor, the GS115-NpgA-ATX grew well and produced 6-MSA quickly until reached a high value of 2.2 g/L by methanol induction for 20 hours. Thereafter, the cells turned to death ascribing to high concentration of antimicrobial 6-MSA. The distribution of 6-MSA changed that during early and late induction phase it existed more in supernatant while during intermediate stage it mainly located intracellular. Different from 6-MSA production strain, recombinant M. purpureus pksCT expression strains for citrinin intermediate production, no matter PksCT located in cytoplasm or in peroxisomes, did not produce any specfic compound. However, both npgA and pksCT transcripted effectively in cells and western blot analysis proved the expression of PPtase. Then the PPTase was expressed and purified, marked by fluorescent probes, and reacted with purified ACP domain and its mutant ACPm of PksCT. Fluoresence was only observed in ACP but not ACPm, indicating that the PPTase worked well with ACP to make it bioactive holo-ACP. Thus, some

Engineered fungal polyketide biosynthesis in Pichia pastoris: a potential excellent host for polyketide production.

PubMed

Gao, Limei; Cai, Menghao; Shen, Wei; Xiao, Siwei; Zhou, Xiangshan; Zhang, Yuanxing

2013-09-08

Polyketides are one of the most important classes of secondary metabolites and usually make good drugs. Currently, heterologous production of fungal polyketides for developing a high potential industrial application system with high production capacity and pharmaceutical feasibility was still at its infancy. Pichia pastoris is a highly successful system for the high production of a variety of heterologous proteins. In this work, we aim to develop a P. pastoris based in vivo fungal polyketide production system for first time and evaluate its feasibility for future industrial application. A recombinant P. pastoris GS115-NpgA-ATX with Aspergillus nidulans phosphopantetheinyl transferase (PPtase) gene npgA and Aspergillus terrus 6-methylsalicylic acid (6-MSA) synthase (6-MSAS) gene atX was constructed. A specific compound was isolated and identified as 6-MSA by HPLC, LC-MS and NMR. Transcription of both genes were detected. In 5-L bioreactor, the GS115-NpgA-ATX grew well and produced 6-MSA quickly until reached a high value of 2.2 g/L by methanol induction for 20 hours. Thereafter, the cells turned to death ascribing to high concentration of antimicrobial 6-MSA. The distribution of 6-MSA changed that during early and late induction phase it existed more in supernatant while during intermediate stage it mainly located intracellular. Different from 6-MSA production strain, recombinant M. purpureus pksCT expression strains for citrinin intermediate production, no matter PksCT located in cytoplasm or in peroxisomes, did not produce any specific compound. However, both npgA and pksCT transcripted effectively in cells and western blot analysis proved the expression of PPtase. Then the PPTase was expressed and purified, marked by fluorescent probes, and reacted with purified ACP domain and its mutant ACPm of PksCT. Fluoresence was only observed in ACP but not ACPm, indicating that the PPTase worked well with ACP to make it bioactive holo-ACP. Thus, some other factors may

Clearing the skies over modular polyketide synthases.

PubMed

Sherman, David H; Smith, Janet L

2006-09-19

Modular polyketide synthases (PKSs) are large multifunctional proteins that synthesize complex polyketide metabolites in microbial cells. A series of recent studies confirm the close protein structural relationship between catalytic domains in the type I mammalian fatty acid synthase (FAS) and the basic synthase unit of the modular PKS. They also establish a remarkable similarity in the overall organization of the type I FAS and the PKS module. This information provides important new conclusions about catalytic domain architecture, function, and molecular recognition that are essential for future efforts to engineer useful polyketide metabolites with valuable biological activities.

Biosynthesis of the salinosporamide A polyketide synthase substrate chloroethylmalonyl-coenzyme A from S-adenosyl-L-methionine.

PubMed

Eustáquio, Alessandra S; McGlinchey, Ryan P; Liu, Yuan; Hazzard, Christopher; Beer, Laura L; Florova, Galina; Alhamadsheh, Mamoun M; Lechner, Anna; Kale, Andrew J; Kobayashi, Yoshihisa; Reynolds, Kevin A; Moore, Bradley S

2009-07-28

Polyketides are among the major classes of bioactive natural products used to treat microbial infections, cancer, and other diseases. Here we describe a pathway to chloroethylmalonyl-CoA as a polyketide synthase building block in the biosynthesis of salinosporamide A, a marine microbial metabolite whose chlorine atom is crucial for potent proteasome inhibition and anticancer activity. S-adenosyl-L-methionine (SAM) is converted to 5'-chloro-5'-deoxyadenosine (5'-ClDA) in a reaction catalyzed by a SAM-dependent chlorinase as previously reported. By using a combination of gene deletions, biochemical analyses, and chemical complementation experiments with putative intermediates, we now provide evidence that 5'-ClDA is converted to chloroethylmalonyl-CoA in a 7-step route via the penultimate intermediate 4-chlorocrotonyl-CoA. Because halogenation often increases the bioactivity of drugs, the availability of a halogenated polyketide building block may be useful in molecular engineering approaches toward polyketide scaffolds.

Preclinical characterization of naturally occurring polyketide cyclophilin inhibitors from the sanglifehrin family.

PubMed

Gregory, Matthew A; Bobardt, Michael; Obeid, Susan; Chatterji, Udayan; Coates, Nigel J; Foster, Teresa; Gallay, Philippe; Leyssen, Pieter; Moss, Steven J; Neyts, Johan; Nur-e-Alam, Mohammad; Paeshuyse, Jan; Piraee, Mahmood; Suthar, Dipen; Warneck, Tony; Zhang, Ming-Qiang; Wilkinson, Barrie

2011-05-01

Cyclophilin inhibitors currently in clinical trials for hepatitis C virus (HCV) are all analogues of cyclosporine (CsA). Sanglifehrins are a group of naturally occurring cyclophilin binding polyketides that are structurally distinct from the cyclosporines and are produced by a microorganism amenable to biosynthetic engineering for lead optimization and large-scale production by fermentation. Preclinical characterization of the potential utility of this class of compounds for the treatment of HCV revealed that the natural sanglifehrins A to D are all more potent than CsA at disrupting formation of the NS5A-CypA, -CypB, and -CypD complexes and at inhibition of CypA, CypB, and CypD isomerase activity. In particular, sanglifehrin B (SfB) was 30- to 50-fold more potent at inhibiting the isomerase activity of all Cyps tested than CsA and was also shown to be a more potent inhibitor of the 1b subgenomic replicon (50% effective concentrations [EC50s] of 0.070 μM and 0.16 μM in Huh 5-2 and Huh 9-13 cells, respectively). Physicochemical and mouse pharmacokinetic analyses revealed low oral bioavailability (F<4%) and low solubility (<25 μM), although the half-lives (t1/2) of SfA and SfB in mouse blood after intravenous (i.v.) dosing were long (t1/2>5 h). These data demonstrate that naturally occurring sanglifehrins are suitable lead compounds for the development of novel analogues that are less immunosuppressive and that have improved metabolism and pharmacokinetic properties.

Probing the Selectivity and Protein•Protein Interactions of a Non-Reducing Fungal Polyketide Synthase Using Mechanism-Based Crosslinkers

PubMed Central

Bruegger, Joel; Haushalter, Bob; Vagstad, Anna; Shakya, Gaurav; Mih, Nathan; Townsend, Craig A.; Burkart, Michael D.; Tsai, Shiou-Chuan

2013-01-01

SUMMARY Protein•protein interactions, which often involve interactions between an acyl carrier protein (ACP) and its partner enzymes, are important for coordinating polyketide biosynthesis. However, the nature of such interactions is not well understood, especially in the fungal non-reducing polyketide synthases (NR-PKSs) that biosynthesize toxic and pharmaceutically important polyketides. Here, we employ a mechanism-based crosslinker to successfully probe ACP and ketosynthase (KS) domain interactions in NR-PKSs. We found that crosslinking efficiency is closely correlated with the strength of ACP•KS interactions, and that KS demonstrates strong starter unit selectivity. We further identified positively charged surface residues by KS mutagenesis, which mediate key interactions with the negatively-charged ACP surface. Such complementary/matching contact pairs can serve as “adapter surfaces” for future efforts to generate new polyketides using NR-PKSs. PMID:23993461

Aromatic polyketide synthases from 127 Fusarium: pas de deux for chemical diversity

USDA-ARS?s Scientific Manuscript database

Fusarium species collectively cause disease on almost all crop plants and produce numerous natural products (NPs), including mycotoxins, of great concern. Many Fusarium NPs are derived from polyketide synthases (PKSs), large enzymes that catalyze the condensation of simple carboxylic acids. To gain ...

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

PubMed Central

Hemmerling, Franziska

2016-01-01

Summary This review highlights the biosynthesis of heterocycles in polyketide natural products with a focus on oxygen and nitrogen-containing heterocycles with ring sizes between 3 and 6 atoms. Heterocycles are abundant structural elements of natural products from all classes and they often contribute significantly to their biological activity. Progress in recent years has led to a much better understanding of their biosynthesis. In this context, plenty of novel enzymology has been discovered, suggesting that these pathways are an attractive target for future studies. PMID:27559404

Engineered Biosynthesis of a Novel Amidated Polyketide, Using the Malonamyl-Specific Initiation Module from the Oxytetracycline Polyketide Synthase

PubMed Central

Zhang, Wenjun; Ames, Brian D.; Tsai, Shiou-Chuan; Tang, Yi

2006-01-01

Tetracyclines are aromatic polyketides biosynthesized by bacterial type II polyketide synthases (PKSs). Understanding the biochemistry of tetracycline PKSs is an important step toward the rational and combinatorial manipulation of tetracycline biosynthesis. To this end, we have sequenced the gene cluster of oxytetracycline (oxy and otc genes) PKS genes from Streptomyces rimosus. Sequence analysis revealed a total of 21 genes between the otrA and otrB resistance genes. We hypothesized that an amidotransferase, OxyD, synthesizes the malonamate starter unit that is a universal building block for tetracycline compounds. In vivo reconstitution using strain CH999 revealed that the minimal PKS and OxyD are necessary and sufficient for the biosynthesis of amidated polyketides. A novel alkaloid (WJ35, or compound 2) was synthesized as the major product when the oxy-encoded minimal PKS, the C-9 ketoreductase (OxyJ), and OxyD were coexpressed in CH999. WJ35 is an isoquinolone compound derived from an amidated decaketide backbone and cyclized with novel regioselectivity. The expression of OxyD with a heterologous minimal PKS did not afford similarly amidated polyketides, suggesting that the oxy-encoded minimal PKS possesses novel starter unit specificity. PMID:16597959

Structural and Biochemical Analyses of Regio- and Stereo-Specificities Observed in a Type II Polyketide Ketoreductase

PubMed Central

Javidpour, Pouya; Korman, Tyler Paz; Shakya, Gaurav; Tsai, Shiou-Chuan

2011-01-01

Type II polyketides include antibiotics such as tetracycline, and chemotherapeutics such as daunorubicin. Type II polyketides are biosynthesized by the type II polyketide synthase (PKS) that consists of 5 – 10 stand-alone domains. In many type II PKSs, the type II ketoreductase (KR) specifically reduce the C9-carbonyl group. How the type II KR achieves such a high regio-specificity, and the nature of stereo-specificity, are not well understood. Sequence alignment of KRs led to a hypothesis that a well-conserved 94-XGG-96 motif may be involved in controlling the stereochemistry. The stereo-specificity of single, double and triple mutant combinations of P94L, G95D and G96D were analyzed in vitro and in vivo for the actinorhodin KR (actKR). The P94L mutation is sufficient to change the stereospecificity of actKR. Binary and ternary crystal structures of both wild type and P94L actKR were solved. Together with assay results, docking simulations, and co-crystal structures, a model for stereochemical control is presented herein that elucidates how type II polyketides are introduced into the substrate pocket such that the C9-carbonyl can be reduced with high regio- and stereo-specificities. The molecular features of actKR important for regio- and stereo-specificities can potentially be applied to biosynthesize new polyketides via protein engineering that rationally controls polyketide ketoreduction. PMID:21506596

The industrial anaerobe Clostridium acetobutylicum uses polyketides to regulate cellular differentiation.

PubMed

Herman, Nicolaus A; Kim, Seong Jong; Li, Jeffrey S; Cai, Wenlong; Koshino, Hiroyuki; Zhang, Wenjun

2017-11-15

Polyketides are an important class of bioactive small molecules valued not only for their diverse therapeutic applications, but also for their role in controlling interesting biological phenotypes in their producing organisms. While numerous polyketides are known to be derived from aerobic organisms, only a single family of polyketides has been identified from anaerobic organisms. Here we uncover a family of polyketides native to the anaerobic bacterium Clostridium acetobutylicum, an organism well-known for its historical use as an industrial producer of the organic solvents acetone, butanol, and ethanol. Through mutational analysis and chemical complementation assays, we demonstrate that these polyketides act as chemical triggers of sporulation and granulose accumulation in this strain. This study represents a significant addition to the body of work demonstrating the existence and importance of polyketides in anaerobes, and showcases a strategy of manipulating the secondary metabolism of an organism to improve traits relevant for industrial applications.

Engineering Biosynthesis of Non-ribosomal Peptides and Polyketides by Directed Evolution.

PubMed

Rui, Zhe; Zhang, Wenjun

2016-01-01

Non-ribosomal peptides (NRPs) and polyketides (PKs) play key roles in pharmaceutical industry due to their promising biological activities. The structural complexity of NRPs and PKs, however, creates significant synthetic challenges for producing these natural products and their analogues by purely chemical means. Alternatively, difficult syntheses can be achieved by using biosynthetic enzymes with improved efficiency and altered selectivity that are acquired from directed evolution. Key to the successful directed evolution is the methodology of screening/selection. This review summarizes the screening/selection strategies that have been employed to improve or modify the functions of non-ribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), in the hope of triggering the wide adoption of the directed evolution approaches in the engineered biosynthesis of NRPs and PKs for drug discovery.

Stalk cell differentiation without polyketides in the cellular slime mold.

PubMed

Sato, Yukie G; Suarez, Teresa; Saito, Tamao

2016-07-01

Polyketides induce prestalk cell differentiation in Dictyostelium. In the double-knockout mutant of the SteelyA and B polyketide synthases, most of the pstA cells-the major part of the prestalk cells-are lost, and we show by whole mount in situ hybridization that expression of prestalk genes is also reduced. Treatment of the double-knockout mutant with the PKS inhibitor cerulenin gave a further reduction, but some pstA cells still remained in the tip region, suggesting the existence of a polyketide-independent subtype of pstA cells. The double-knockout mutant and cerulenin-treated parental Ax2 cells form fruiting bodies with fragile, single-cell layered stalks after cerulenin treatment. Our results indicate that most pstA cells are induced by polyketides, but the pstA cells at the very tip of the slug are induced in some other way. In addition, a fruiting body with a single-cell layered, vacuolated stalk can form without polyketides.

Preclinical Characterization of Naturally Occurring Polyketide Cyclophilin Inhibitors from the Sanglifehrin Family▿†

PubMed Central

Gregory, Matthew A.; Bobardt, Michael; Obeid, Susan; Chatterji, Udayan; Coates, Nigel J.; Foster, Teresa; Gallay, Philippe; Leyssen, Pieter; Moss, Steven J.; Neyts, Johan; Nur-e-Alam, Mohammad; Paeshuyse, Jan; Piraee, Mahmood; Suthar, Dipen; Warneck, Tony; Zhang, Ming-Qiang; Wilkinson, Barrie

2011-01-01

Cyclophilin inhibitors currently in clinical trials for hepatitis C virus (HCV) are all analogues of cyclosporine (CsA). Sanglifehrins are a group of naturally occurring cyclophilin binding polyketides that are structurally distinct from the cyclosporines and are produced by a microorganism amenable to biosynthetic engineering for lead optimization and large-scale production by fermentation. Preclinical characterization of the potential utility of this class of compounds for the treatment of HCV revealed that the natural sanglifehrins A to D are all more potent than CsA at disrupting formation of the NS5A-CypA, -CypB, and -CypD complexes and at inhibition of CypA, CypB, and CypD isomerase activity. In particular, sanglifehrin B (SfB) was 30- to 50-fold more potent at inhibiting the isomerase activity of all Cyps tested than CsA and was also shown to be a more potent inhibitor of the 1b subgenomic replicon (50% effective concentrations [EC50s] of 0.070 μM and 0.16 μM in Huh 5-2 and Huh 9-13 cells, respectively). Physicochemical and mouse pharmacokinetic analyses revealed low oral bioavailability (F < 4%) and low solubility (<25 μM), although the half-lives (t1/2) of SfA and SfB in mouse blood after intravenous (i.v.) dosing were long (t1/2 > 5 h). These data demonstrate that naturally occurring sanglifehrins are suitable lead compounds for the development of novel analogues that are less immunosuppressive and that have improved metabolism and pharmacokinetic properties. PMID:21383094

HSQC-TOCSY Fingerprinting-Directed Discovery of Antiplasmodial Polyketides from the Marine Ascidian-Derived Streptomyces sp. (USC-16018).

PubMed

Buedenbender, Larissa; Robertson, Luke P; Lucantoni, Leonardo; Avery, Vicky M; Kurtböke, D İpek; Carroll, Anthony R

2018-05-30

Chemical investigations on the fermentation extract obtained from an ascidian-derived Streptomyces sp. (USC-16018) yielded a new ansamycin polyketide, herbimycin G ( 1 ), as well as a known macrocyclic polyketide, elaiophylin ( 2 ), and four known diketopiperazines ( 3 ⁻ 6 ). The structures of the compounds were elucidated based on 1D/2D NMR and MS data. The absolute configuration of 1 was established by comparison of experimental and predicted electronic circular dichroism (ECD) data. Antiplasmodial activities were tested for the natural products against chloroquine sensitive (3D7) and chloroquine resistant (Dd2) Plasmodium falciparum strains; the two polyketides ( 1 ⁻ 2 ) demonstrated an inhibition of >75% against both parasite strains and while 2 was highly cytotoxic, herbimycin G ( 1 ) showed no cytotoxicity and good predicted water solubility.

Evolution of polyketide synthesis in a Dothideomycete forest pathogen

USDA-ARS?s Scientific Manuscript database

Fungal secondary metabolites have many important biological roles and some, like the toxic polyketide aflatoxin, have been intensively studied at the genetic level. Complete sets of polyketide synthase (PKS) genes can now be identified in fungal pathogens by whole genome sequencing and studied in or...

Total Biosynthesis and Diverse Applications of the Nonribosomal Peptide-Polyketide Siderophore Yersiniabactin

PubMed Central

Ahmadi, Mahmoud Kamal; Fawaz, Samar; Jones, Charles H.; Zhang, Guojian

2015-01-01

Yersiniabactin (Ybt) is a mixed nonribosomal peptide-polyketide natural product natively produced by the pathogen Yersinia pestis. The compound enables iron scavenging capabilities upon host infection and is biosynthesized by a nonribosomal peptide synthetase featuring a polyketide synthase module. This pathway has been engineered for expression and biosynthesis using Escherichia coli as a heterologous host. In the current work, the biosynthetic process for Ybt formation was improved through the incorporation of a dedicated step to eliminate the need for exogenous salicylate provision. When this improvement was made, the compound was tested in parallel applications that highlight the metal-chelating nature of the compound. In the first application, Ybt was assessed as a rust remover, demonstrating a capacity of ∼40% compared to a commercial removal agent and ∼20% relative to total removal capacity. The second application tested Ybt in removing copper from a variety of nonbiological and biological solution mixtures. Success across a variety of media indicates potential utility in diverse scenarios that include environmental and biomedical settings. PMID:26025901

Alternative Sigma Factor Over-Expression Enables Heterologous Expression of a Type II Polyketide Biosynthetic Pathway in Escherichia coli

PubMed Central

Stevens, David Cole; Conway, Kyle R.; Pearce, Nelson; Villegas-Peñaranda, Luis Roberto; Garza, Anthony G.; Boddy, Christopher N.

2013-01-01

Background Heterologous expression of bacterial biosynthetic gene clusters is currently an indispensable tool for characterizing biosynthetic pathways. Development of an effective, general heterologous expression system that can be applied to bioprospecting from metagenomic DNA will enable the discovery of a wealth of new natural products. Methodology We have developed a new Escherichia coli-based heterologous expression system for polyketide biosynthetic gene clusters. We have demonstrated the over-expression of the alternative sigma factor σ54 directly and positively regulates heterologous expression of the oxytetracycline biosynthetic gene cluster in E. coli. Bioinformatics analysis indicates that σ54 promoters are present in nearly 70% of polyketide and non-ribosomal peptide biosynthetic pathways. Conclusions We have demonstrated a new mechanism for heterologous expression of the oxytetracycline polyketide biosynthetic pathway, where high-level pleiotropic sigma factors from the heterologous host directly and positively regulate transcription of the non-native biosynthetic gene cluster. Our bioinformatics analysis is consistent with the hypothesis that heterologous expression mediated by the alternative sigma factor σ54 may be a viable method for the production of additional polyketide products. PMID:23724102

Allelopathic Polyketides from an Endolichenic Fungus Myxotrichum SP. by Using OSMAC Strategy.

PubMed

Yuan, Chao; Guo, Yu-Hua; Wang, Hai-Ying; Ma, Xiao-Jun; Jiang, Tao; Zhao, Jun-Ling; Zou, Zhong-Mei; Ding, Gang

2016-02-03

Three new polyketides myxotritones A-C (2-4), together with a new natural product 7,8-dihydro-7R,8S-dihydroxy-3,7-dimethyl-2-benzopyran-6-one (1) were obtained from the endolichenic fungus Myxotrichum sp. by using OMSAC (One Strain, Many Compounds) method. The planar structures of these new compounds were determined by NMR experiment and HRESIMS data, and the absolute configuration of 1 was established by X-ray diffraction, and the stereochemistry of the new compounds 2-4 were determined by same biosynthesis origin, and similar CD spectra with 1. Allelopathic test showed that compound 4 significantly retarded root elongation of Arabidopsis thaliana seed, indicating that this fungus might contribute to the defense of its host lichen. From the view of biosynthetic pathway, all four compounds 1-4 might be originated from Non-Reduced Polyketide synthase (NR-PKS).

A crotonyl-CoA reductase-carboxylase independent pathway for assembly of unusual alkylmalonyl-CoA polyketide synthase extender units

NASA Astrophysics Data System (ADS)

Ray, Lauren; Valentic, Timothy R.; Miyazawa, Takeshi; Withall, David M.; Song, Lijiang; Milligan, Jacob C.; Osada, Hiroyuki; Takahashi, Shunji; Tsai, Shiou-Chuan; Challis, Gregory L.

2016-12-01

Type I modular polyketide synthases assemble diverse bioactive natural products. Such multienzymes typically use malonyl and methylmalonyl-CoA building blocks for polyketide chain assembly. However, in several cases more exotic alkylmalonyl-CoA extender units are also known to be incorporated. In all examples studied to date, such unusual extender units are biosynthesized via reductive carboxylation of α, β-unsaturated thioesters catalysed by crotonyl-CoA reductase/carboxylase (CCRC) homologues. Here we show using a chemically-synthesized deuterium-labelled mechanistic probe, and heterologous gene expression experiments that the unusual alkylmalonyl-CoA extender units incorporated into the stambomycin family of polyketide antibiotics are assembled by direct carboxylation of medium chain acyl-CoA thioesters. X-ray crystal structures of the unusual β-subunit of the acyl-CoA carboxylase (YCC) responsible for this reaction, alone and in complex with hexanoyl-CoA, reveal the molecular basis for substrate recognition, inspiring the development of methodology for polyketide bio-orthogonal tagging via incorporation of 6-azidohexanoic acid and 8-nonynoic acid into novel stambomycin analogues.

Polyketide intermediate mimics as probes for revealing cryptic stereochemistry of ketoreductase domains.

PubMed

Li, Yang; Fiers, William D; Bernard, Steffen M; Smith, Janet L; Aldrich, Courtney C; Fecik, Robert A

2014-12-19

Among natural product families, polyketides have shown the most promise for combinatorial biosynthesis of natural product-like libraries. Though recent research in the area has provided many mechanistic revelations, a basic-level understanding of kinetic and substrate tolerability is still needed before the full potential of combinatorial biosynthesis can be realized. We have developed a novel set of chemical probes for the study of ketoreductase domains of polyketide synthases. This chemical tool-based approach was validated using the ketoreductase of pikromycin module 2 (PikKR2) as a model system. Triketide substrate mimics 12 and 13 were designed to increase stability (incorporating a nonhydrolyzable thioether linkage) and minimize nonessential functionality (truncating the phosphopantetheinyl arm). PikKR2 reduction product identities as well as steady-state kinetic parameters were determined by a combination of LC-MS/MS analysis of synthetic standards and a NADPH consumption assay. The d-hydroxyl product is consistent with bioinformatic analysis and results from a complementary biochemical and molecular biological approach. When compared to widely employed substrates in previous studies, diketide 63 and trans-decalone 64, substrates 12 and 13 showed 2-10 fold lower K(M) values (2.4 ± 0.8 and 7.8 ± 2.7 mM, respectively), indicating molecular recognition of intermediate-like substrates. Due to an abundance of the nonreducable enol-tautomer, the k(cat) values were attenuated by as much as 15-336 fold relative to known substrates. This study reveals the high stereoselectivity of PikKR2 in the face of gross substrate permutation, highlighting the utility of a chemical probe-based approach in the study of polyketide ketoreductases.

Novel natural food antimicrobials.

PubMed

Juneja, Vijay K; Dwivedi, Hari P; Yan, Xianghe

2012-01-01

Naturally occurring antimicrobial compounds could be applied as food preservatives to protect food quality and extend the shelf life of foods and beverages. These compounds are naturally produced and isolated from various sources, including plants, animals and microorganisms, in which they constitute part of host defense systems. Many naturally occurring compounds, such as nisin, plant essential oils, and natamycin, have been widely studied and are reported to be effective in their potential role as antimicrobial agents against spoilage and pathogenic microorganisms. Although some of these natural antimicrobials are commercially available and applied in food processing, their efficacy, consumer acceptance and regulation are not well defined. This manuscript reviews natural antimicrobial compounds with reference to their applications in food when applied individually or in combination with other hurdles. It also reviews the mechanism of action of selected natural antimicrobials, factors affecting their antimicrobial activities, and future prospects for use of natural antimicrobials in the food industry.

Biochemical and Structural Basis for Controlling Chemical Modularity in Fungal Polyketide Biosynthesis

DOE PAGES

Winter, Jaclyn M.; Cascio, Duilio; Dietrich, David; ...

2015-07-14

Modular collaboration between iterative fungal polyketide synthases (IPKSs) is an important mechanism for generating structural diversity of polyketide natural products. Inter-PKS communication and substrate channeling are controlled in large by the starter unit acyl carrier protein transacylase (SAT) domain found in the accepting IPKS module. Here in this study, we reconstituted the modular biosynthesis of the benzaldehyde core of the chaetoviridin and chaetomugilin azaphilone natural products using the IPKSs CazF and CazM. Our studies revealed a critical role of CazM’s SAT domain in selectively transferring a highly reduced triketide product from CazF. In contrast, a more oxidized triketide that ismore » also produced by CazF and required in later stages of biosynthesis of the final product is not recognized by the SAT domain. The structural basis for the acyl unit selectivity was uncovered by the first X-ray structure of a fungal SAT domain, highlighted by a covalent hexanoyl thioester intermediate in the SAT active site. Finally, the crystal structure of SAT domain will enable protein engineering efforts aimed at mixing and matching different IPKS modules for the biosynthesis of new compounds.« less

Hybrid polyketide synthases

DOEpatents

Fortman, Jeffrey L.; Hagen, Andrew; Katz, Leonard; Keasling, Jay D.; Poust, Sean; Zhang, Jingwei; Zotchev, Sergey

2016-05-10

The present invention provides for a polyketide synthase (PKS) capable of synthesizing an even-chain or odd-chain diacid or lactam or diamine. The present invention also provides for a host cell comprising the PKS and when cultured produces the even-chain diacid, odd-chain diacid, or KAPA. The present invention also provides for a host cell comprising the PKS capable of synthesizing a pimelic acid or KAPA, and when cultured produces biotin.

Antibacterial polyketides from the jellyfish-derived fungus Paecilomyces variotii.

PubMed

Liu, Juan; Li, Famei; Kim, Eun La; Li, Jian Lin; Hong, Jongki; Bae, Kyung Sook; Chung, Hae Young; Kim, Hyung Sik; Jung, Jee H

2011-08-26

Four new polyketides (1-4) were isolated from the fungus Paecilomyces variotii, which was derived from the jellyfish Nemopilema nomurai. The planar structures and relative configurations of these polyketides were elucidated on the basis of spectroscopic analyses, including 2D NMR experiments. The compounds showed inhibitory activity against pathogenic bacteria including methicillin-resistant Staphylococcus aureus 3089 and multi-drug-resistant Vibrio parahemolyticus 7001 with MIC values in the range 5-40 μg/mL.

Genomic and transcriptomic analyses reveal differential regulation of diverse terpenoid and polyketides secondary metabolites in Hericium erinaceus.

PubMed

Chen, Juan; Zeng, Xu; Yang, Yan Long; Xing, Yong Mei; Zhang, Qi; Li, Jia Mei; Ma, Ke; Liu, Hong Wei; Guo, Shun Xing

2017-08-31

The lion's mane mushroom Hericium erinaceus is a famous traditional medicinal fungus credited with anti-dementia activity and a producer of cyathane diterpenoid natural products (erinacines) useful against nervous system diseases. To date, few studies have explored the biosynthesis of these compounds, although their chemical synthesis is known. Here, we report the first genome and tanscriptome sequence of the medicinal fungus H. erinaceus. The size of the genome is 39.35 Mb, containing 9895 gene models. The genome of H. erinaceus reveals diverse enzymes and a large family of cytochrome P450 (CYP) proteins involved in the biosynthesis of terpenoid backbones, diterpenoids, sesquiterpenes and polyketides. Three gene clusters related to terpene biosynthesis and one gene cluster for polyketides biosynthesis (PKS) were predicted. Genes involved in terpenoid biosynthesis were generally upregulated in mycelia, while the PKS gene was upregulated in the fruiting body. Comparative genome analysis of 42 fungal species of Basidiomycota revealed that most edible and medicinal mushroom show many more gene clusters involved in terpenoid and polyketide biosynthesis compared to the pathogenic fungi. None of the gene clusters for terpenoid or polyketide biosynthesis were predicted in the poisonous mushroom Amanita muscaria. Our findings may facilitate future discovery and biosynthesis of bioactive secondary metabolites from H. erinaceus and provide fundamental information for exploring the secondary metabolites in other Basidiomycetes.

Divergent Mechanistic Routes for the Formation of gem-Dimethyl Groups in the Biosynthesis of Complex Polyketides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poust, S; Phelan, RM; Deng, K

The gem-dimethyl groups in polyketide-derived natural products add steric bulk and, accordingly, lend increased stability to medicinal compounds, however, our ability to rationally incorporate this functional group in modified natural products is limited. In order to characterize the mechanism of gem-dimethyl group formation, with a goal toward engineering of novel compounds containing this moiety, the gem-dimethyl group producing polyketide synthase (PKS) modules of yersiniabactin and epothilone were characterized using mass spectrometry. The work demonstrated, contrary to the canonical understanding of reaction order in PKSs, that methylation can precede condensation in gem-dimethyl group producing PKS modules. Experiments showed that both PKSsmore » are able to use dimethylmalonyl acyl carrier protein (ACP) as an extender unit. Interestingly, for epothilone module8, use of dimethylmalonyl-ACP appeared to be the sole route to form a gem-dimethylated product, while the yersiniabactin PKS could methylate before or after ketosynthase condensation.« less

Tagging polyketides/non-ribosomal peptides with a clickable functionality and applications

PubMed Central

Zhu, Xuejun; Zhang, Wenjun

2015-01-01

Bioorthogonal chemistry has recently emerged to be one of the most powerful tools in drug discovery and chemical biology. The exploration of it has successfully advanced the field of natural product research. In this Perspective, we survey current strategies for the installation of chemical handles into the molecular scaffolds of several major classes of natural products, including polyketides (PKs), non-ribosomal peptides (NRPs), and their hybrids. By tagging these natural products with chemical handles and coupling them with subsequent bioorthogonal reactions, researchers have visualized and studied the mode of action of natural products, as well as synthesized derivatives with better pharmaceutical properties. We conclude this Perspective by considering two questions: is there a general way to synthesize tagged PKs/NRPs? Does natural product labeling have a broader impact in the field of natural product research beyond current known applications? PMID:25815285

The LINKS motif zippers trans-acyltransferase polyketide synthase assembly lines into a biosynthetic megacomplex

PubMed Central

Gay, Darren C.; Wagner, Drew T.; Meinke, Jessica L.; Zogzas, Charles E.; Gay, Glen R.; Keatinge-Clay, Adrian T.

2016-01-01

Polyketides such as the clinically-valuable antibacterial agent mupirocin are constructed by architecturally-sophisticated assembly lines known as trans-acyltransferase polyketide synthases. Organelle-sized megacomplexes composed of several copies of trans-acyltransferase polyketide synthase assembly lines have been observed by others through transmission electron microscopy to be located at the Bacillus subtilis plasma membrane, where the synthesis and export of the antibacterial polyketide bacillaene takes place. In this work we analyze ten crystal structures of trans-acyltransferase polyketide synthases ketosynthase domains, seven of which are reported here for the first time, to characterize a motif capable of zippering assembly lines into a megacomplex. While each of the three-helix LINKS (Laterally-INteracting Ketosynthase Sequence) motifs is observed to similarly dock with a spatially-reversed copy of itself through hydrophobic and ionic interactions, the amino acid sequences of this motif are not conserved. Such a code is appropriate for mediating homotypic contacts between assembly lines to ensure the ordered self-assembly of a noncovalent, yet tightly-knit, enzymatic network. LINKS-mediated lateral interactions would also have the effect of bolstering the vertical association of the polypeptides that comprise a polyketide synthase assembly line. PMID:26724270

Evolution of Chemical Diversity in a Group of Non-Reduced Polyketide Gene Clusters: Using Phylogenetics to Inform the Search for Novel Fungal Natural Products

PubMed Central

Throckmorton, Kurt; Wiemann, Philipp; Keller, Nancy P.

2015-01-01

Fungal polyketides are a diverse class of natural products, or secondary metabolites (SMs), with a wide range of bioactivities often associated with toxicity. Here, we focus on a group of non-reducing polyketide synthases (NR-PKSs) in the fungal phylum Ascomycota that lack a thioesterase domain for product release, group V. Although widespread in ascomycete taxa, this group of NR-PKSs is notably absent in the mycotoxigenic genus Fusarium and, surprisingly, found in genera not known for their secondary metabolite production (e.g., the mycorrhizal genus Oidiodendron, the powdery mildew genus Blumeria, and the causative agent of white-nose syndrome in bats, Pseudogymnoascus destructans). This group of NR-PKSs, in association with the other enzymes encoded by their gene clusters, produces a variety of different chemical classes including naphthacenediones, anthraquinones, benzophenones, grisandienes, and diphenyl ethers. We discuss the modification of and transitions between these chemical classes, the requisite enzymes, and the evolution of the SM gene clusters that encode them. Integrating this information, we predict the likely products of related but uncharacterized SM clusters, and we speculate upon the utility of these classes of SMs as virulence factors or chemical defenses to various plant, animal, and insect pathogens, as well as mutualistic fungi. PMID:26378577

Convergence of isoprene and polyketide biosynthetic machinery: isoprenyl-S-carrier proteins in the pksX pathway of Bacillus subtilis.

PubMed

Calderone, Christopher T; Kowtoniuk, Walter E; Kelleher, Neil L; Walsh, Christopher T; Dorrestein, Pieter C

2006-06-13

The pksX gene cluster from Bacillus subtilis is predicted to encode the biosynthesis of an as yet uncharacterized hybrid nonribosomal peptide/polyketide secondary metabolite. We used a combination of biochemical and mass spectrometric techniques to assign functional roles to the proteins AcpK, PksC, PksL, PksF, PksG, PksH, and PksI, and we conclude that they act to incorporate an acetate-derived beta-methyl branch on an acetoacetyl-S-carrier protein and ultimately generate a Delta(2)-isoprenyl-S-carrier protein. This work highlights the power of mass spectrometry to elucidate the functions of orphan biosynthetic enzymes, and it details a mechanism by which single-carbon beta-branches can be inserted into polyketide-like structures. This pathway represents a noncanonical route to the construction of prenyl units and serves as a prototype for the intersection of isoprenoid and polyketide biosynthetic manifolds in other natural product biosynthetic pathways.

Producing alpha-olefins using polyketide synthases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fortman, Jeffrey L.; Katz, Leonard; Steen, Eric J.

2018-01-02

The present invention provides for a polyketide synthase (PKS) capable of synthesizing an .alpha.-olefin, such as 1-hexene or butadiene. The present invention also provides for a host cell comprising the PKS and when cultured produces the .alpha.-olefin.

The LINKS motif zippers trans-acyltransferase polyketide synthase assembly lines into a biosynthetic megacomplex.

PubMed

Gay, Darren C; Wagner, Drew T; Meinke, Jessica L; Zogzas, Charles E; Gay, Glen R; Keatinge-Clay, Adrian T

2016-03-01

Polyketides such as the clinically-valuable antibacterial agent mupirocin are constructed by architecturally-sophisticated assembly lines known as trans-acyltransferase polyketide synthases. Organelle-sized megacomplexes composed of several copies of trans-acyltransferase polyketide synthase assembly lines have been observed by others through transmission electron microscopy to be located at the Bacillus subtilis plasma membrane, where the synthesis and export of the antibacterial polyketide bacillaene takes place. In this work we analyze ten crystal structures of trans-acyltransferase polyketide synthases ketosynthase domains, seven of which are reported here for the first time, to characterize a motif capable of zippering assembly lines into a megacomplex. While each of the three-helix LINKS (Laterally-INteracting Ketosynthase Sequence) motifs is observed to similarly dock with a spatially-reversed copy of itself through hydrophobic and ionic interactions, the amino acid sequences of this motif are not conserved. Such a code is appropriate for mediating homotypic contacts between assembly lines to ensure the ordered self-assembly of a noncovalent, yet tightly-knit, enzymatic network. LINKS-mediated lateral interactions would also have the effect of bolstering the vertical association of the polypeptides that comprise a polyketide synthase assembly line. Copyright © 2015 Elsevier Inc. All rights reserved.

The type I fatty acid and polyketide synthases: a tale of two megasynthases

PubMed Central

Tsai, Shiou-Chuan

2008-01-01

This review chronicles the synergistic growth of the fields of fatty acid and polyketide synthesis over the last century. In both animal fatty acid synthases and modular polyketide synthases, similar catalytic elements are covalently linked in the same order in megasynthases. Whereas in fatty acid synthases the basic elements of the design remain immutable, guaranteeing the faithful production of saturated fatty acids, in the modular polyketide synthases, the potential of the basic design has been exploited to the full for the elaboration of a wide range of secondary metabolites of extraordinary structural diversity. PMID:17898897

Lessons from 455 Fusarium polyketide synthases

USDA-ARS?s Scientific Manuscript database

In fungi, polyketide synthases (PKSs) synthesize a structurally diverse array of secondary metabolites (SMs) with a range of biological activities. The most studied SMs are toxic to animals and/or plants, alter plant growth, have beneficial pharmaceutical activities, and/or are brightly colored pigm...

Polyketide mimetics yield structural and mechanistic insights into product template domain function in nonreducing polyketide synthases

PubMed Central

Barajas, Jesus F.; Shakya, Gaurav; Moreno, Gabriel; Rivera, Heriberto; Jackson, David R.; Topper, Caitlyn L.; Vagstad, Anna L.; La Clair, James J.; Townsend, Craig A.; Burkart, Michael D.; Tsai, Shiou-Chuan

2017-01-01

Product template (PT) domains from fungal nonreducing polyketide synthases (NR-PKSs) are responsible for controlling the aldol cyclizations of poly-β-ketone intermediates assembled during the catalytic cycle. Our ability to understand the high regioselective control that PT domains exert is hindered by the inaccessibility of intrinsically unstable poly-β-ketones for in vitro studies. We describe here the crystallographic application of “atom replacement” mimetics in which isoxazole rings linked by thioethers mimic the alternating sites of carbonyls in the poly-β-ketone intermediates. We report the 1.8-Å cocrystal structure of the PksA PT domain from aflatoxin biosynthesis with a heptaketide mimetic tethered to a stably modified 4′-phosphopantetheine, which provides important empirical evidence for a previously proposed mechanism of PT-catalyzed cyclization. Key observations support the proposed deprotonation at C4 of the nascent polyketide by the catalytic His1345 and the role of a protein-coordinated water network to selectively activate the C9 carbonyl for nucleophilic addition. The importance of the 4′-phosphate at the distal end of the pantetheine arm is demonstrated to both facilitate delivery of the heptaketide mimetic deep into the PT active site and anchor one end of this linear array to precisely meter C4 into close proximity to the catalytic His1345. Additional structural features, docking simulations, and mutational experiments characterize protein–substrate mimic interactions, which likely play roles in orienting and stabilizing interactions during the native multistep catalytic cycle. These findings afford a view of a polyketide “atom-replaced” mimetic in a NR-PKS active site that could prove general for other PKS domains. PMID:28484029

Systematic Domain Swaps of Iterative, Nonreducing Polyketide Synthases Provide a Mechanistic Understanding and Rationale For Catalytic Reprogramming

PubMed Central

2015-01-01

Iterative, nonreducing polyketide synthases (NR-PKSs) are multidomain enzymes responsible for the construction of the core architecture of aromatic polyketide natural products in fungi. Engineering these enzymes for the production of non-native metabolites has been a long-standing goal. We conducted a systematic survey of in vitro “domain swapped” NR-PKSs using an enzyme deconstruction approach. The NR-PKSs were dissected into mono- to multidomain fragments and recombined as noncognate pairs in vitro, reconstituting enzymatic activity. The enzymes used in this study produce aromatic polyketides that are representative of the four main chemical features set by the individual NR-PKS: starter unit selection, chain-length control, cyclization register control, and product release mechanism. We found that boundary conditions limit successful chemistry, which are dependent on a set of underlying enzymatic mechanisms. Crucial for successful redirection of catalysis, the rate of productive chemistry must outpace the rate of spontaneous derailment and thioesterase-mediated editing. Additionally, all of the domains in a noncognate system must interact efficiently if chemical redirection is to proceed. These observations refine and further substantiate current understanding of the mechanisms governing NR-PKS catalysis. PMID:24815013

Natural Colorants: Food Colorants from Natural Sources.

PubMed

Sigurdson, Gregory T; Tang, Peipei; Giusti, M Mónica

2017-02-28

The color of food is often associated with the flavor, safety, and nutritional value of the product. Synthetic food colorants have been used because of their high stability and low cost. However, consumer perception and demand have driven the replacement of synthetic colorants with naturally derived alternatives. Natural pigment applications can be limited by lower stability, weaker tinctorial strength, interactions with food ingredients, and inability to match desired hues. Therefore, no single naturally derived colorant can serve as a universal alternative for a specified synthetic colorant in all applications. This review summarizes major environmental and biological sources for natural colorants as well as nature-identical counterparts. Chemical characteristics of prevalent pigments, including anthocyanins, carotenoids, betalains, and chlorophylls, are described. The possible applications and hues (warm, cool, and achromatic) of currently used natural pigments, such as anthocyanins as red and blue colorants, and possible future alternatives, such as purple violacein and red pyranoanthocyanins, are also discussed.

Evolutionary distinctiveness of fatty acid and polyketide synthesis in eukaryotes

PubMed Central

Kohli, Gurjeet S; John, Uwe; Van Dolah, Frances M; Murray, Shauna A

2016-01-01

Fatty acids, which are essential cell membrane constituents and fuel storage molecules, are thought to share a common evolutionary origin with polyketide toxins in eukaryotes. While fatty acids are primary metabolic products, polyketide toxins are secondary metabolites that are involved in ecologically relevant processes, such as chemical defence, and produce the adverse effects of harmful algal blooms. Selection pressures on such compounds may be different, resulting in differing evolutionary histories. Surprisingly, some studies of dinoflagellates have suggested that the same enzymes may catalyse these processes. Here we show the presence and evolutionary distinctiveness of genes encoding six key enzymes essential for fatty acid production in 13 eukaryotic lineages for which no previous sequence data were available (alveolates: dinoflagellates, Vitrella, Chromera; stramenopiles: bolidophytes, chrysophytes, pelagophytes, raphidophytes, dictyochophytes, pinguiophytes, xanthophytes; Rhizaria: chlorarachniophytes, haplosporida; euglenids) and 8 other lineages (apicomplexans, bacillariophytes, synurophytes, cryptophytes, haptophytes, chlorophyceans, prasinophytes, trebouxiophytes). The phylogeny of fatty acid synthase genes reflects the evolutionary history of the organism, indicating selection to maintain conserved functionality. In contrast, polyketide synthase gene families are highly expanded in dinoflagellates and haptophytes, suggesting relaxed constraints in their evolutionary history, while completely absent from some protist lineages. This demonstrates a vast potential for the production of bioactive polyketide compounds in some lineages of microbial eukaryotes, indicating that the evolution of these compounds may have played an important role in their ecological success. PMID:26784357

Genetic construction and functional analysis of hybrid polyketide synthases containing heterologous acyl carrier proteins.

PubMed Central

Khosla, C; McDaniel, R; Ebert-Khosla, S; Torres, R; Sherman, D H; Bibb, M J; Hopwood, D A

1993-01-01

The gene that encodes the acyl carrier protein (ACP) of the actinorhodin polyketide synthase (PKS) of Streptomyces coelicolor A3(2) was replaced with homologs from the granaticin, oxytetracycline, tetracenomycin, and putative frenolicin polyketide synthase gene clusters. All of the replacements led to expression of functional synthases, and the recombinants synthesized aromatic polyketides similar in chromatographic properties to actinorhodin or to shunt products produced by mutants defective in the actinorhodin pathway. Some regions within the ACP were also shown to be interchangeable and allow production of a functional hybrid ACP. Structural analysis of the most abundant polyketide product of one of the recombinants by electrospray mass spectrometry suggested that it is identical to mutactin, a previously characterized shunt product of an actVII mutant (deficient in cyclase and dehydrase activities). Quantitative differences in the product profiles of strains that express the various hybrid synthases were observed. These can be explained, at least in part, by differences in ribosome-binding sites upstream of each ACP gene, implying either that the ACP concentration in some strains is rate limiting to overall PKS activity or that the level of ACP expression also influences the expression of another enzyme(s) encoded by a downstream gene(s) in the same operon as the actinorhodin ACP gene. These results reaffirm the idea that construction of hybrid polyketide synthases will be a useful approach for dissecting the molecular basis of the specificity of PKS-catalyzed reactions. However, they also point to the need for reducing the chemical complexity of the approach by minimizing the diversity of polyketide products synthesized in strains that produce recombinant polyketide synthases. Images PMID:8468280

Mother natural: Motivations and associations for consuming natural foods.

PubMed

Moscato, Emily M; Machin, Jane E

2018-02-01

Natural is perceived as innately positive and is a widely sought-after attribute in food products. The natural food industry continues to grow in response to rising consumer demand. This qualitative study explored mothers' motivations for purchasing and consuming natural food products for themselves and their families. Mothers are an important population because of their disproportionate influence on household food consumption. We employed participant photography and a series of three weekly focus groups to derive a rich understanding of the activities surrounding and motivations behind seeking natural in everyday buying decisions. Five major themes were identified. First, natural nurtures well-being: physical, psychological, social, and emotional health. Second, natural behaves "supernaturally," allowing positive attributes to be transmitted from the source to the recipient. Third, natural is associated with authenticity, providing a sense of trust, transparency, and control. Fourth, consuming natural reinforces the socially constructed idea of a good mother. Lastly, the preference for natural does not always translate into purchase; mothers face compromises because of conflicting priorities and resources. Understanding mothers' multiple motivations provides deeper insight into the attraction for natural products. The findings have application in positioning interventions for more nutritional eating and revising regulations on the food label natural. Copyright © 2017 Elsevier Ltd. All rights reserved.

Producing dicarboxylic acids using polyketide synthases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katz, Leonard; Fortman, Jeffrey L.; Keasling, Jay D.

The present invention provides for a polyketide synthase (PKS) capable of synthesizing a dicarboxylic acid (diacid). Such diacids include diketide-diacids and triketide-diacids. The invention includes recombinant nucleic acid encoding the PKS, and host cells comprising the PKS. The invention also includes methods for producing the diacids.

Novel Artificial Natural Products Against Breast Cancer Through Combinatorial Biosynthesis

DTIC Science & Technology

2002-07-01

compounds normally produced by a certain strain. Our investigations on the discovery of novel natural metabolites using type II polyketide synthase ...limitations, shall be included on any reproduction hereof which includes any part of the portions subject to such limitations. THIS TECHNICAL REPORT HAS... polyketides remain the central group of natural products in this research area, since this class of natural products form one of the largest and most

Identification of olivetolic acid cyclase from Cannabis sativa reveals a unique catalytic route to plant polyketides.

PubMed

Gagne, Steve J; Stout, Jake M; Liu, Enwu; Boubakir, Zakia; Clark, Shawn M; Page, Jonathan E

2012-07-31

Δ(9)-Tetrahydrocannabinol (THC) and other cannabinoids are responsible for the psychoactive and medicinal properties of Cannabis sativa L. (marijuana). The first intermediate in the cannabinoid biosynthetic pathway is proposed to be olivetolic acid (OA), an alkylresorcinolic acid that forms the polyketide nucleus of the cannabinoids. OA has been postulated to be synthesized by a type III polyketide synthase (PKS) enzyme, but so far type III PKSs from cannabis have been shown to produce catalytic byproducts instead of OA. We analyzed the transcriptome of glandular trichomes from female cannabis flowers, which are the primary site of cannabinoid biosynthesis, and searched for polyketide cyclase-like enzymes that could assist in OA cyclization. Here, we show that a type III PKS (tetraketide synthase) from cannabis trichomes requires the presence of a polyketide cyclase enzyme, olivetolic acid cyclase (OAC), which catalyzes a C2-C7 intramolecular aldol condensation with carboxylate retention to form OA. OAC is a dimeric α+β barrel (DABB) protein that is structurally similar to polyketide cyclases from Streptomyces species. OAC transcript is present at high levels in glandular trichomes, an expression profile that parallels other cannabinoid pathway enzymes. Our identification of OAC both clarifies the cannabinoid pathway and demonstrates unexpected evolutionary parallels between polyketide biosynthesis in plants and bacteria. In addition, the widespread occurrence of DABB proteins in plants suggests that polyketide cyclases may play an overlooked role in generating plant chemical diversity.

Forazoline A: Marine-derived polyketide with antifungal in vivo efficacy

DOE PAGES

Wyche, Thomas P.; Piotrowski, Jeff S.; Hou, Yanpeng; ...

2014-09-04

Forazoline A, a novel antifungal polyketide with in vivo efficacy against Candida albicans, was discovered using LCMS-based metabolomics to investigate marine-invertebrate-associated bacteria. Forazoline A had a highly unusual and unprecedented skeleton. Acquisition of 13C– 13C gCOSY and 13C– 15N HMQC NMR data provided the direct carbon–carbon and carbon–nitrogen connectivity, respectively. This approach represents the first example of determining direct 13C– 15N connectivity for a natural product. In this paper, using yeast chemical genomics, we propose that forazoline A operated through a new mechanism of action with a phenotypic outcome of disrupting membrane integrity.

Polyketide synthesis genes associated with toxin production in two species of Gambierdiscus (Dinophyceae).

PubMed

Kohli, Gurjeet S; John, Uwe; Figueroa, Rosa I; Rhodes, Lesley L; Harwood, D Tim; Groth, Marco; Bolch, Christopher J S; Murray, Shauna A

2015-05-28

Marine microbial protists, in particular, dinoflagellates, produce polyketide toxins with ecosystem-wide and human health impacts. Species of Gambierdiscus produce the polyether ladder compounds ciguatoxins and maitotoxins, which can lead to ciguatera fish poisoning, a serious human illness associated with reef fish consumption. Genes associated with the biosynthesis of polyether ladder compounds are yet to be elucidated, however, stable isotope feeding studies of such compounds consistently support their polyketide origin indicating that polyketide synthases are involved in their biosynthesis. Here, we report the toxicity, genome size, gene content and transcriptome of Gambierdiscus australes and G. belizeanus. G. australes produced maitotoxin-1 and maitotoxin-3, while G. belizeanus produced maitotoxin-3, for which cell extracts were toxic to mice by IP injection (LD50 = 3.8 mg kg(-1)). The gene catalogues comprised 83,353 and 84,870 unique contigs, with genome sizes of 32.5 ± 3.7 Gbp and 35 ± 0.88 Gbp, respectively, and are amongst the most comprehensive yet reported from a dinoflagellate. We found three hundred and six genes involved in polyketide biosynthesis, including one hundred and ninety-two ketoacyl synthase transcripts, which formed five unique phylogenetic clusters. Two clusters were unique to these maitotoxin-producing dinoflagellate species, suggesting that they may be associated with maitotoxin biosynthesis. This work represents a significant step forward in our understanding of the genetic basis of polyketide production in dinoflagellates, in particular, species responsible for ciguatera fish poisoning.

Allergens/Antigens, toxins and polyketides of important Aspergillus species.

PubMed

Bhetariya, Preetida J; Madan, Taruna; Basir, Seemi Farhat; Varma, Anupam; Usha, Sarma P

2011-04-01

The medical, agricultural and biotechnological importance of the primitive eukaryotic microorganisms, the Fungi was recognized way back in 1920. Among various groups of fungi, the Aspergillus species are studied in great detail using advances in genomics and proteomics to unravel biological and molecular mechanisms in these fungi. Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Aspergillus nidulans and Aspergillus terreus are some of the important species relevant to human, agricultural and biotechnological applications. The potential of Aspergillus species to produce highly diversified complex biomolecules such as multifunctional proteins (allergens, antigens, enzymes) and polyketides is fascinating and demands greater insight into the understanding of these fungal species for application to human health. Recently a regulator gene for secondary metabolites, LaeA has been identified. Gene mining based on LaeA has facilitated new metabolites with antimicrobial activity such as emericellamides and antitumor activity such as terrequinone A from A. nidulans. Immunoproteomic approach was reported for identification of few novel allergens for A. fumigatus. In this context, the review is focused on recent developments in allergens, antigens, structural and functional diversity of the polyketide synthases that produce polyketides of pharmaceutical and biological importance. Possible antifungal drug targets for development of effective antifungal drugs and new strategies for development of molecular diagnostics are considered.

Synthetic biology approaches to fluorinated polyketides

PubMed Central

Thuronyi, Benjamin W.; Chang, Michelle C. Y.

2016-01-01

Conspectus The catalytic diversity of living systems offers a broad range of opportunities for developing new methods to produce small molecule targets such as fuels, materials, and pharmaceuticals. In addition to providing cost-effective and renewable methods for large-scale commercial processes, the exploration of the unusual chemical phenotypes found in living organisms can also enable the expansion of chemical space for discovery of novel function by combining orthogonal attributes from both synthetic and biological chemistry. In this context, we have focused on the development of new fluorine chemistry using synthetic biology approaches. While fluorine has become an important feature in compounds of synthetic origin, the scope of biological fluorine chemistry in living systems is limited, with fewer than 20 organofluorine natural products identified to date. In order to expand the diversity of biosynthetically accessible organofluorines, we have begun to develop methods for the site-selective introduction of fluorine into complex natural products by engineering biosynthetic machinery to incorporate fluorinated building blocks. To gain insight into how both enzyme active sites and metabolic pathways can be evolved to manage and select for fluorinated compounds, we have studied one of the only characterized natural hosts for organofluorine biosynthesis, the soil microbe Streptomyces cattleya. This information provides a template for designing engineered organofluorine enzymes, pathways, and hosts and has allowed us to initiate construction of enzymatic and cellular pathways for the production of fluorinated polyketides. PMID:25719427

An automated Genomes-to-Natural Products platform (GNP) for the discovery of modular natural products.

PubMed

Johnston, Chad W; Skinnider, Michael A; Wyatt, Morgan A; Li, Xiang; Ranieri, Michael R M; Yang, Lian; Zechel, David L; Ma, Bin; Magarvey, Nathan A

2015-09-28

Bacterial natural products are a diverse and valuable group of small molecules, and genome sequencing indicates that the vast majority remain undiscovered. The prediction of natural product structures from biosynthetic assembly lines can facilitate their discovery, but highly automated, accurate, and integrated systems are required to mine the broad spectrum of sequenced bacterial genomes. Here we present a genome-guided natural products discovery tool to automatically predict, combinatorialize and identify polyketides and nonribosomal peptides from biosynthetic assembly lines using LC-MS/MS data of crude extracts in a high-throughput manner. We detail the directed identification and isolation of six genetically predicted polyketides and nonribosomal peptides using our Genome-to-Natural Products platform. This highly automated, user-friendly programme provides a means of realizing the potential of genetically encoded natural products.

ClusterCAD: a computational platform for type I modular polyketide synthase design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eng, Clara H.; Backman, Tyler W H; Bailey, Constance B.

Here, we present ClusterCAD, a web-based toolkit designed to leverage the collinear structure and deterministic logic of type I modular polyketide synthases (PKSs) for synthetic biology applications. The unique organization of these megasynthases, combined with the diversity of their catalytic domain building blocks, has fueled an interest in harnessing the biosynthetic potential of PKSs for the microbial production of both novel natural product analogs and industrially relevant small molecules. However, a limited theoretical understanding of the determinants of PKS fold and function poses a substantial barrier to the design of active variants, and identifying strategies to reliably construct functional PKSmore » chimeras remains an active area of research. In this work, we formalize a paradigm for the design of PKS chimeras and introduce ClusterCAD as a computational platform to streamline and simplify the process of designing experiments to test strategies for engineering PKS variants. ClusterCAD provides chemical structures with stereochemistry for the intermediates generated by each PKS module, as well as sequence- and structure-based search tools that allow users to identify modules based either on amino acid sequence or on the chemical structure of the cognate polyketide intermediate. ClusterCAD can be accessed at https://clustercad.jbei.org and at http://clustercad.igb.uci.edu.« less

ClusterCAD: a computational platform for type I modular polyketide synthase design

DOE PAGES

Eng, Clara H.; Backman, Tyler W H; Bailey, Constance B.; ...

2017-10-11

Here, we present ClusterCAD, a web-based toolkit designed to leverage the collinear structure and deterministic logic of type I modular polyketide synthases (PKSs) for synthetic biology applications. The unique organization of these megasynthases, combined with the diversity of their catalytic domain building blocks, has fueled an interest in harnessing the biosynthetic potential of PKSs for the microbial production of both novel natural product analogs and industrially relevant small molecules. However, a limited theoretical understanding of the determinants of PKS fold and function poses a substantial barrier to the design of active variants, and identifying strategies to reliably construct functional PKSmore » chimeras remains an active area of research. In this work, we formalize a paradigm for the design of PKS chimeras and introduce ClusterCAD as a computational platform to streamline and simplify the process of designing experiments to test strategies for engineering PKS variants. ClusterCAD provides chemical structures with stereochemistry for the intermediates generated by each PKS module, as well as sequence- and structure-based search tools that allow users to identify modules based either on amino acid sequence or on the chemical structure of the cognate polyketide intermediate. ClusterCAD can be accessed at https://clustercad.jbei.org and at http://clustercad.igb.uci.edu.« less

Diversity-oriented combinatorial biosynthesis of benzenediol lactone scaffolds by subunit shuffling of fungal polyketide synthases.

PubMed

Xu, Yuquan; Zhou, Tong; Zhang, Shuwei; Espinosa-Artiles, Patricia; Wang, Luoyi; Zhang, Wei; Lin, Min; Gunatilaka, A A Leslie; Zhan, Jixun; Molnár, István

2014-08-26

Combinatorial biosynthesis aspires to exploit the promiscuity of microbial anabolic pathways to engineer the synthesis of new chemical entities. Fungal benzenediol lactone (BDL) polyketides are important pharmacophores with wide-ranging bioactivities, including heat shock response and immune system modulatory effects. Their biosynthesis on a pair of sequentially acting iterative polyketide synthases (iPKSs) offers a test case for the modularization of secondary metabolic pathways into "build-couple-pair" combinatorial synthetic schemes. Expression of random pairs of iPKS subunits from four BDL model systems in a yeast heterologous host created a diverse library of BDL congeners, including a polyketide with an unnatural skeleton and heat shock response-inducing activity. Pairwise heterocombinations of the iPKS subunits also helped to illuminate the innate, idiosyncratic programming of these enzymes. Even in combinatorial contexts, these biosynthetic programs remained largely unchanged, so that the iPKSs built their cognate biosynthons, coupled these building blocks into chimeric polyketide intermediates, and catalyzed intramolecular pairing to release macrocycles or α-pyrones. However, some heterocombinations also provoked stuttering, i.e., the relaxation of iPKSs chain length control to assemble larger homologous products. The success of such a plug and play approach to biosynthesize novel chemical diversity bodes well for bioprospecting unnatural polyketides for drug discovery.

Engineering a Polyketide Synthase for In Vitro Production of Adipic Acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagen, Andrew; Poust, Sean; Rond, Tristan de

2015-10-26

Polyketides have enormous structural diversity, yet polyketide synthases (PKSs) have thus far been engineered to produce only drug candidates or derivatives thereof. Thousands of other molecules, including commodity and specialty chemicals, could be synthesized using PKSs if composing hybrid PKSs from well-characterized parts derived from natural PKSs was more efficient. Here, using modern mass spectrometry techniques as an essential part of the design–build–test cycle, we engineered a chimeric PKS to enable production one of the most widely used commodity chemicals, adipic acid. To accomplish this, we introduced heterologous reductive domains from various PKS clusters into the borrelidin PKS’ first extensionmore » module, which we previously showed produces a 3-hydroxy-adipoyl intermediate when coincubated with the loading module and a succinyl-CoA starter unit. Acyl-ACP intermediate analysis revealed an unexpected bottleneck at the dehydration step, which was overcome by introduction of a carboxyacyl-processing dehydratase domain. Appending a thioesterase to the hybrid PKS enabled the production of free adipic acid. Using acyl-intermediate based techniques to “debug” PKSs as described here, it should one day be possible to engineer chimeric PKSs to produce a variety of existing commodity and specialty chemicals, as well as thousands of chemicals that are difficult to produce from petroleum feedstocks using traditional synthetic chemistry.« less

Naturally Occurring Food Toxins

PubMed Central

Dolan, Laurie C.; Matulka, Ray A.; Burdock, George A.

2010-01-01

Although many foods contain toxins as a naturally-occurring constituent or, are formed as the result of handling or processing, the incidence of adverse reactions to food is relatively low. The low incidence of adverse effects is the result of some pragmatic solutions by the US Food and Drug Administration (FDA) and other regulatory agencies through the creative use of specifications, action levels, tolerances, warning labels and prohibitions. Manufacturers have also played a role by setting limits on certain substances and developing mitigation procedures for process-induced toxins. Regardless of measures taken by regulators and food producers to protect consumers from natural food toxins, consumption of small levels of these materials is unavoidable. Although the risk for toxicity due to consumption of food toxins is fairly low, there is always the possibility of toxicity due to contamination, overconsumption, allergy or an unpredictable idiosyncratic response. The purpose of this review is to provide a toxicological and regulatory overview of some of the toxins present in some commonly consumed foods, and where possible, discuss the steps that have been taken to reduce consumer exposure, many of which are possible because of the unique process of food regulation in the United States. PMID:22069686

Episodic memory for natural and transformed food.

PubMed

Aiello, Marilena; Vignando, Miriam; Foroni, Francesco; Pergola, Giulio; Rossi, Paola; Silveri, Maria Caterina; Rumiati, Raffaella I

2018-05-10

It has been proposed that the conceptual knowledge of food and its putative subdivision into natural (i.e., fruit/vegetables) and transformed (i.e., food that underwent thermic or non-thermic processing) may follow the living/non-living distinction. In the present study, we investigated whether the advantage for living things compared to non-living things observed in episodic memory (the so-called animacy effect) extends to natural foods and transformed foods respectively. We pursued this issue in two experiments. In Experiment 1, we measured episodic memory for natural and transformed foods in young participants. In Experiment 2, we enrolled dementia-free centenarians, patients with Alzheimer's disease (DAT), Progressive primary aphasia (PPA), and healthy controls whose episodic memory was also tested for living/non-living things. Results showed that young participants had better recognition memory for transformed foods compared to natural foods. This difference disappeared in centenarians and patients. However, centenarians and PPA exhibited enhanced levels of false alarms (FA) with natural food, and DAT patients with both natural and transformed food. As far as the living/non-living distinction is concerned, the episodic memory for the living category appears more resilient to the decline compared to the non-living category in patients, particularly those with PPA. In conclusion, our study shows that transformed food is better remembered than natural food, suggesting that it is more salient and possibly relevant from an evolutionary perspective. The natural/transformed distinction appears susceptible to erosion only in the presence of a high degree of episodic memory impairment. These results offer novel insight on episodic memory of food, and also extend the current knowledge on the animacy effect in episodic memory. Copyright © 2018 Elsevier Ltd. All rights reserved.

Informatic analysis reveals Legionella as a source of novel natural products.

PubMed

Johnston, Chad W; Plumb, Jonathan; Li, Xiang; Grinstein, Sergio; Magarvey, Nathan A

2016-06-01

Microbial natural products are a crucial source of bioactive molecules and unique chemical scaffolds. Despite their importance, rediscovery of known natural products from established productive microbes has led to declining interest, even while emergent genomic data suggest that the majority of microbial natural products remain to be discovered. Now, new sources of microbial natural products must be defined in order to provide chemical scaffolds for the next generation of small molecules for therapeutic, agricultural, and industrial purposes. In this work, we use specialized bioinformatic programs, genetic knockouts, and comparative metabolomics to define the genus Legionella as a new source of novel natural products. We show that Legionella spp. hold a diverse collection of biosynthetic gene clusters for the production of polyketide and nonribosomal peptide natural products. To confirm this bioinformatic survey, we create targeted mutants of L. pneumophila and use comparative metabolomics to identify a novel polyketide surfactant. Using spectroscopic techniques, we show that this polyketide possesses a new chemical scaffold, and firmly demonstrate that this unexplored genus is a source for novel natural products.

Isolation of polyketides from Prymnesium parvum (Haptophyta) and their detection by liquid chromatography/mass spectrometry metabolic fingerprint analysis.

PubMed

Manning, Schonna R; La Claire Ii, John W

2013-11-15

Prymnesium parvum is a microalga that forms blooms coupled with the presence of potent exotoxins; however, no chemical standards are currently available for the toxins. Streamlined methods are presented for the separation and enrichment of polyketide toxins, prymnesin-1 (prym1) and prymnesin-2 (prym2). Prymnesins were separated by reversed-phase chromatography and detected by positive-mode electrospray ionization MS to generate a unique metabolic fingerprint. More than 10 ions were detected and mass assignments were in agreement with predicted isotopic distributions for the intact compounds and related fragments; ions occurred as multiply protonated species and with common salt adducts. The most prevalent ion was observed at 919.88 m/z, which represents the aglycone [prymagly+2H](2+) backbone structure common to both molecules. Expanded mass spectra for this and related ions were in excellent agreement (<0.5ppm) with empirically derived spectra based on elemental composition and naturally occurring isotopes. These investigations have confirmed the isolation of polyketide prymnesins from whole cells, which heretofore has not been reproduced since their original characterization. Moreover, this study represents the first time these compounds have been verified in aqueous materials. These tools should allow the direct identification and analysis of polyketide prymnesins, which will greatly improve our understanding of these toxins in P. parvum. Copyright © 2013 Elsevier Inc. All rights reserved.

Food applications of natural antimicrobial compounds.

PubMed

Lucera, Annalisa; Costa, Cristina; Conte, Amalia; Del Nobile, Matteo A

2012-01-01

In agreement with the current trend of giving value to natural and renewable resources, the use of natural antimicrobial compounds, particularly in food and biomedical applications, becomes very frequent. The direct addition of natural compounds to food is the most common method of application, even if numerous efforts have been made to find alternative solutions to the aim of avoiding undesirable inactivation. Dipping, spraying, and coating treatment of food with active solutions are currently applied to product prior to packaging as valid options. The aim of the current work is to give an overview on the use of natural compounds in food sector. In particular, the review will gather numerous case-studies of meat, fish, dairy products, minimally processed fruit and vegetables, and cereal-based products where these compounds found application.

Food applications of natural antimicrobial compounds

PubMed Central

Lucera, Annalisa; Costa, Cristina; Conte, Amalia; Del Nobile, Matteo A.

2012-01-01

In agreement with the current trend of giving value to natural and renewable resources, the use of natural antimicrobial compounds, particularly in food and biomedical applications, becomes very frequent. The direct addition of natural compounds to food is the most common method of application, even if numerous efforts have been made to find alternative solutions to the aim of avoiding undesirable inactivation. Dipping, spraying, and coating treatment of food with active solutions are currently applied to product prior to packaging as valid options. The aim of the current work is to give an overview on the use of natural compounds in food sector. In particular, the review will gather numerous case-studies of meat, fish, dairy products, minimally processed fruit and vegetables, and cereal-based products where these compounds found application. PMID:23060862

Anatomy of the β-branching enzyme of polyketide biosynthesis and its interaction with an acyl-ACP substrate.

PubMed

Maloney, Finn P; Gerwick, Lena; Gerwick, William H; Sherman, David H; Smith, Janet L

2016-09-13

Alkyl branching at the β position of a polyketide intermediate is an important variation on canonical polyketide natural product biosynthesis. The branching enzyme, 3-hydroxy-3-methylglutaryl synthase (HMGS), catalyzes the aldol addition of an acyl donor to a β-keto-polyketide intermediate acceptor. HMGS is highly selective for two specialized acyl carrier proteins (ACPs) that deliver the donor and acceptor substrates. The HMGS from the curacin A biosynthetic pathway (CurD) was examined to establish the basis for ACP selectivity. The donor ACP (CurB) had high affinity for the enzyme (Kd = 0.5 μM) and could not be substituted by the acceptor ACP. High-resolution crystal structures of HMGS alone and in complex with its donor ACP reveal a tight interaction that depends on exquisite surface shape and charge complementarity between the proteins. Selectivity is explained by HMGS binding to an unusual surface cleft on the donor ACP, in a manner that would exclude the acceptor ACP. Within the active site, HMGS discriminates between pre- and postreaction states of the donor ACP. The free phosphopantetheine (Ppant) cofactor of ACP occupies a conserved pocket that excludes the acetyl-Ppant substrate. In comparison with HMG-CoA (CoA) synthase, the homologous enzyme from primary metabolism, HMGS has several differences at the active site entrance, including a flexible-loop insertion, which may account for the specificity of one enzyme for substrates delivered by ACP and the other by CoA.

Filamentous fungi for production of food additives and processing aids.

PubMed

Archer, David B; Connerton, Ian F; MacKenzie, Donald A

2008-01-01

Filamentous fungi are metabolically versatile organisms with a very wide distribution in nature. They exist in association with other species, e.g. as lichens or mycorrhiza, as pathogens of animals and plants or as free-living species. Many are regarded as nature's primary degraders because they secrete a wide variety of hydrolytic enzymes that degrade waste organic materials. Many species produce secondary metabolites such as polyketides or peptides and an increasing range of fungal species is exploited commercially as sources of enzymes and metabolites for food or pharmaceutical applications. The recent availability of fungal genome sequences has provided a major opportunity to explore and further exploit fungi as sources of enzymes and metabolites. In this review chapter we focus on the use of fungi in the production of food additives but take a largely pre-genomic, albeit a mainly molecular, view of the topic.

Unexpected link between polyketide synthase and calcium carbonate biomineralization.

PubMed

Hojo, Motoki; Omi, Ai; Hamanaka, Gen; Shindo, Kazutoshi; Shimada, Atsuko; Kondo, Mariko; Narita, Takanori; Kiyomoto, Masato; Katsuyama, Yohei; Ohnishi, Yasuo; Irie, Naoki; Takeda, Hiroyuki

2015-01-01

Calcium carbonate biominerals participate in diverse physiological functions. Despite intensive studies, little is known about how mineralization is initiated in organisms. We analyzed the medaka spontaneous mutant, ha, defective in otolith (calcareous ear stone) formation. ha lacks a trigger for otolith mineralization, and the causative gene was found to encode polyketide synthase (pks), a multifunctional enzyme mainly found in bacteria, fungi, and plant. Subsequent experiments demonstrate that the products of medaka PKS, most likely polyketides or their derivatives, act as nucleation facilitators in otolith mineralization. The generality of this novel PKS function is supported by the essential role of echinoderm PKS in calcareous skeleton formation together with the presence of PKSs in a much wider range of animals from coral to vertebrates. The present study first links PKS to biomineralization and provides a genetic cue for biogeochemistry of carbon and calcium cycles.

Improved heterologous production of the nonribosomal peptide-polyketide siderophore yersiniabactin through metabolic engineering and induction optimization.

PubMed

Ahmadi, Mahmoud Kamal; Pfeifer, Blaine A

2016-11-01

Biosynthesis of complex natural products like polyketides and nonribosomal peptides using Escherichia coli as a heterologous host provides an opportunity to access these molecules. The value in doing so stems from the fact that many compounds hold some therapeutic or other beneficial property and their original production hosts are intractable for a variety of reasons. In this work, metabolic engineering and induction variable optimization were used to increase production of the polyketide-nonribosomal peptide compound yersiniabactin, a siderophore that has been utilized to selectively remove metals from various solid and aqueous samples. Specifically, several precursor substrate support pathways were altered through gene expression and exogenous supplementation in order to boost production of the final compound. The gene expression induction process was also analyzed to identify the temperatures and inducer concentrations resulting in highest final production levels. When combined, yersiniabactin production was extended to ∼175 mg L -1 . © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1412-1417, 2016. © 2016 American Institute of Chemical Engineers.

Synthesis of polyketide stereoarrays enabled by a traceless oxonia-Cope rearrangement.

PubMed

Yang, Lin; He, Guoli; Yin, Ruifeng; Zhu, Lili; Wang, Xiaoxia; Hong, Ran

2014-10-20

Polyketide antibiotics bearing skipped polyols represent a synthetic challenge. A SiCl4-promoted oxonia-Cope rearrangement of syn,syn-2-vinyl-1,3-diols was developed to forge an array of 1,5-pentenediols, thus providing versatile motifs for the preparation of 1,2,3,5-stereoarrays in a highly stereoselective manner. Further exploration with Sn(OTf)2 realized the rearrangement of a cross-aldehyde which tactically warrants the utility of the current approach to access complex polyketides. The origin of high stereoselectivity is attributed to a chairlike anti-conformation of the oxonium ion intermediate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polyketide synthases of Diaporthe helianthi and involvement of DhPKS1 in virulence on sunflower.

PubMed

Ruocco, Michelina; Baroncelli, Riccardo; Cacciola, Santa Olga; Pane, Catello; Monti, Maurilia Maria; Firrao, Giuseppe; Vergara, Mariarosaria; Magnano di San Lio, Gaetano; Vannacci, Giovanni; Scala, Felice

2018-01-06

The early phases of Diaporthe helianthi pathogenesis on sunflower are characterized by the production of phytotoxins that may play a role in host colonisation. In previous studies, phytotoxins of a polyketidic nature were isolated and purified from culture filtrates of virulent strains of D. helianthi isolated from sunflower. A highly aggressive isolate (7/96) from France contained a gene fragment of a putative nonaketide synthase (lovB) which was conserved in a virulent D. helianthi population. In order to investigate the role of polyketide synthases in D. helianthi 7/96, a draft genome of this isolate was examined. We were able to find and phylogenetically analyse 40 genes putatively coding for polyketide synthases (PKSs). Analysis of their domains revealed that most PKS genes of D. helianthi are reducing PKSs, whereas only eight lacked reducing domains. Most of the identified PKSs have orthologs shown to be virulence factors or genetic determinants for toxin production in other pathogenic fungi. One of the genes (DhPKS1) corresponded to the previously cloned D. helianthi lovB gene fragment and clustered with a nonribosomal peptide synthetase (NRPS) -PKS hybrid/lovastatin nonaketide like A. nidulans LovB. We used DhPKS1 as a case study and carried out its disruption through Agrobacterium-mediated transformation in the isolate 7/96. D. helianthi DhPKS1 deleted mutants were less virulent to sunflower compared to the wild type, indicating a role for this gene in the pathogenesis of the fungus. The PKS sequences analysed and reported here constitute a new genomic resource that will be useful for further research on the biology, ecology and evolution of D. helianthi and generally of fungal plant pathogens.

Improved pestalotiollide B production by deleting competing polyketide synthase genes in Pestalotiopsis microspora.

PubMed

Chen, Longfei; Li, Yingying; Zhang, Qian; Wang, Dan; Akhberdi, Oren; Wei, Dongsheng; Pan, Jiao; Zhu, Xudong

2017-02-01

Pestalotiollide B, an analog of dibenzodioxocinones which are inhibitors of cholesterol ester transfer proteins, is produced by Pestalotiopsis microspora NK17. To increase the production of pestalotiollide B, we attempted to eliminate competing polyketide products by deleting the genes responsible for their biosynthesis. We successfully deleted 41 out of 48 putative polyketide synthases (PKSs) in the genome of NK17. Nine of the 41 PKS deleted strains had significant increased production of pestalotiollide B (P < 0.05). For instance, deletion of pks35, led to an increase of pestalotiollide B by 887%. We inferred that these nine PKSs possibly lead to branch pathways that compete for precursors with pestalotiollide B, or that convert the product. Deletion of some other PKS genes such as pks8 led to a significant decrease of pestalotiollide B, suggesting they are responsible for its biosynthesis. Our data demonstrated that improvement of pestalotiollide B production can be achieved by eliminating competing polyketides.

A Polyketide Synthase Encoded by the Gene An15g07920 Is Involved in the Biosynthesis of Ochratoxin A in Aspergillus niger.

PubMed

Zhang, Jian; Zhu, Liuyang; Chen, Haoyu; Li, Min; Zhu, Xiaojuan; Gao, Qiang; Wang, Depei; Zhang, Ying

2016-12-28

The polyketide synthase gene An15g07920 was known in Aspergillus niger CBS 513.88 as putatively involved in the production of ochratoxin A (OTA). Genome resequencing analysis revealed that the gene An15g07920 is also present in the ochratoxin-producing A. niger strain 1062. Disruption of An15g07920 in A. niger 1062 removed its capacity to biosynthesize ochratoxin β (OTβ), ochratoxin α (OTα), and OTA. These results indicate that the polyketide synthase encoded by An15g07920 is a crucial player in the biosynthesis of OTA, in the pathway prior to the phenylalanine ligation step. The gene An15g07920 reached its maximum transcription level before OTA accumulation reached its highest level, confirming that gene transcription precedes OTA production. These findings will not only help explain the mechanism of OTA production in A. niger but also provide necessary information for the development of effective diagnostic, preventive, and control strategies to reduce the risk of OTA contamination in foods.

Structural basis for olivetolic acid formation by a polyketide cyclase from Cannabis sativa.

PubMed

Yang, Xinmei; Matsui, Takashi; Kodama, Takeshi; Mori, Takahiro; Zhou, Xiaoxi; Taura, Futoshi; Noguchi, Hiroshi; Abe, Ikuro; Morita, Hiroyuki

2016-03-01

In polyketide biosynthesis, ring formation is one of the key diversification steps. Olivetolic acid cyclase (OAC) from Cannabis sativa, involved in cannabinoid biosynthesis, is the only known plant polyketide cyclase. In addition, it is the only functionally characterized plant α+β barrel (DABB) protein that catalyzes the C2-C7 aldol cyclization of the linear pentyl tetra-β-ketide CoA as the substrate, to generate olivetolic acid (OA). Herein, we solved the OAC apo and OAC-OA complex binary crystal structures at 1.32 and 1.70 Å resolutions, respectively. The crystal structures revealed that the enzyme indeed belongs to the DABB superfamily, as previously proposed, and possesses a unique active-site cavity containing the pentyl-binding hydrophobic pocket and the polyketide binding site, which have never been observed among the functionally and structurally characterized bacterial polyketide cyclases. Furthermore, site-directed mutagenesis studies indicated that Tyr72 and His78 function as acid/base catalysts at the catalytic center. Structural and/or functional studies of OAC suggested that the enzyme lacks thioesterase and aromatase activities. These observations demonstrated that OAC employs unique catalytic machinery utilizing acid/base catalytic chemistry for the formation of the precursor of OA. The structural and functional insights obtained in this work thus provide the foundation for analyses of the plant polyketide cyclases that will be discovered in the future. Structural data reported in this paper are available in the Protein Data Bank under the accession numbers 5B08 for the OAC apo, 5B09 for the OAC-OA binary complex and 5B0A, 5B0B, 5B0C, 5B0D, 5B0E, 5B0F and 5B0G for the OAC His5Q, Ile7F, Tyr27F, Tyr27W, Val59M, Tyr72F and His78S mutant enzymes, respectively. © 2016 Federation of European Biochemical Societies.

Novel food packaging systems with natural antimicrobial agents.

PubMed

Irkin, Reyhan; Esmer, Ozlem Kizilirmak

2015-10-01

A new type of packaging that combines food packaging materials with antimicrobial substances to control microbial surface contamination of foods to enhance product microbial safety and to extend shelf-life is attracting interest in the packaging industry. Several antimicrobial compounds can be combined with different types of packaging materials. But in recent years, since consumer demand for natural food ingredients has increased because of safety and availability, these natural compounds are beginning to replace the chemical additives in foods and are perceived to be safer and claimed to alleviate safety concerns. Recent research studies are mainly focused on the application of natural antimicrobials in food packaging system. Biologically derived compounds like bacteriocins, phytochemicals, enzymes can be used in antimicrobial food packaging. The aim of this review is to give an overview of most important knowledge about application of natural antimicrobial packagings with model food systems and their antimicrobial effects on food products.

Nanostructures for delivery of natural antimicrobials in food.

PubMed

Lopes, Nathalie Almeida; Brandelli, Adriano

2017-04-10

Natural antimicrobial compounds are a topic of utmost interest in food science due to the increased demand for safe and high-quality foods with minimal processing. The use of nanostructures is an interesting alternative to protect and delivery antimicrobials in food, also providing controlled release of natural compounds such as bacteriocins and antimicrobial proteins, and also for delivery of plant derived antimicrobials. A diversity of nanostructures are capable of trapping natural antimicrobials maintaining the stability of substances that are frequently sensitive to food processing and storage conditions. This article provides an overview on natural antimicrobials incorporated in nanostructures, showing an effective antimicrobial activity on a diversity of food spoilage and pathogenic microorganisms.

Polyketide Derivatives from Annona muricata Linn Leaves as Potencial Anticancer Material by Combination Treatment With Doxorubicin on Hela Cell Line

NASA Astrophysics Data System (ADS)

Artanti, A. N.; Astirin, O. P.; Prayito, A.; Widiyaningsih, R. F.; Prihapsara, F.

2017-02-01

One of the compounds found effication as an anticancer agent on cervical cancer is acetogenin, a polyketide compound that is abundant in Annona muricata L. leaves. This study has been done to examine polyketide derivatives was isolated from Annona muricata L. which has potency to induce apoptosis by p53 expression on hela cell line. An approach recently develop to overcome side effect of chemoterapeutic agent is used of combined chemoterapeutic agent, i.e doxorubicin. The determination of cytotoxic combination activity from polyketide derivative and doxorubicin was evaluated using MTT assay to obtain the value of CI (combination index). The expression of p53 profile was evaluated by immunohistochemistry on hela cell line. Data analysis showed that combination of polyketide derivative from Annona muricata L. (38,5 µg/ml) and doxorubicin with all of concentration performed synergistic effect on hela cell line with CI value from 0,33 - 0,65. The analysis on immucytochemistry showed that polyketide derivative from Annona muricata L. leaves could enhance p53 pathway significantly on hela cell line.

Characterization of the Biosynthetic Genes for 10,11-Dehydrocurvularin, a Heat Shock Response-Modulating Anticancer Fungal Polyketide from Aspergillus terreus

PubMed Central

Xu, Yuquan; Espinosa-Artiles, Patricia; Schubert, Vivien; Xu, Ya-ming; Zhang, Wei; Lin, Min; Gunatilaka, A. A. Leslie; Süssmuth, Roderich

2013-01-01

10,11-Dehydrocurvularin is a prevalent fungal phytotoxin with heat shock response and immune-modulatory activities. It features a dihydroxyphenylacetic acid lactone polyketide framework with structural similarities to resorcylic acid lactones like radicicol or zearalenone. A genomic locus was identified from the dehydrocurvularin producer strain Aspergillus terreus AH-02-30-F7 to reveal genes encoding a pair of iterative polyketide synthases (A. terreus CURS1 [AtCURS1] and AtCURS2) that are predicted to collaborate in the biosynthesis of 10,11-dehydrocurvularin. Additional genes in this locus encode putative proteins that may be involved in the export of the compound from the cell and in the transcriptional regulation of the cluster. 10,11-Dehydrocurvularin biosynthesis was reconstituted in Saccharomyces cerevisiae by heterologous expression of the polyketide synthases. Bioinformatic analysis of the highly reducing polyketide synthase AtCURS1 and the nonreducing polyketide synthase AtCURS2 highlights crucial biosynthetic programming differences compared to similar synthases involved in resorcylic acid lactone biosynthesis. These differences lead to the synthesis of a predicted tetraketide starter unit that forms part of the 12-membered lactone ring of dehydrocurvularin, as opposed to the penta- or hexaketide starters in the 14-membered rings of resorcylic acid lactones. Tetraketide N-acetylcysteamine thioester analogues of the starter unit were shown to support the biosynthesis of dehydrocurvularin and its analogues, with yeast expressing AtCURS2 alone. Differential programming of the product template domain of the nonreducing polyketide synthase AtCURS2 results in an aldol condensation with a different regiospecificity than that of resorcylic acid lactones, yielding the dihydroxyphenylacetic acid scaffold characterized by an S-type cyclization pattern atypical for fungal polyketides. PMID:23335766

Redundant synthesis of a conidial polyketide by two distinct secondary metabolite clusters in Aspergillus fumigatus

PubMed Central

Throckmorton, Kurt; Lim, Fang Yun; Kontoyiannis, Dimitrios P.; Zheng, Weifa; Keller, Nancy P.

2016-01-01

Summary Filamentous fungi are renowned for the production of bioactive secondary metabolites. Typically, one distinct metabolite is generated from a specific secondary metabolite cluster. Here, we characterize the newly described trypacidin (tpc) cluster in the opportunistic human pathogen Aspergillus fumigatus. We find that this cluster as well as the previously characterized endocrocin (enc) cluster both contribute to the production of the spore metabolite endocrocin. Whereas trypacidin is eliminated when only tpc cluster genes are deleted, endocrocin production is only eliminated when both the tpc and enc non-reducing polyketide synthase-encoding genes, tpcC and encA, respectively, are deleted. EncC, an anthrone oxidase, converts the product released from EncA to endocrocin as a final product. In contrast, endocrocin synthesis by the tpc cluster likely results from incomplete catalysis by TpcK (a putative decarboxylase), as its deletion results in a nearly 10-fold increase in endocrocin production. We suggest endocrocin is likely a shunt product in all related non-reducing polyketide synthase clusters containing homologues of TpcK and TpcL (a putative anthrone oxidase), e.g. geodin and monodictyphenone. This finding represents an unusual example of two physically discrete secondary metabolite clusters generating the same natural product in one fungal species by distinct routes. PMID:26242966

Phylogenomic and Domain Analysis of Iterative Polyketide Synthases in Aspergillus Species

PubMed Central

Lin, Shu-Hsi; Yoshimoto, Miwa; Lyu, Ping-Chiang; Tang, Chuan-Yi; Arita, Masanori

2012-01-01

Aspergillus species are industrially and agriculturally important as fermentors and as producers of various secondary metabolites. Among them, fungal polyketides such as lovastatin and melanin are considered a gold mine for bioactive compounds. We used a phylogenomic approach to investigate the distribution of iterative polyketide synthases (PKS) in eight sequenced Aspergilli and classified over 250 fungal genes. Their genealogy by the conserved ketosynthase (KS) domain revealed three large groups of nonreducing PKS, one group inside bacterial PKS, and more than 9 small groups of reducing PKS. Polyphyly of nonribosomal peptide synthase (NRPS)-PKS genes raised questions regarding the recruitment of the elegant conjugation machinery. High rates of gene duplication and divergence were frequent. All data are accessible through our web database at http://metabolomics.jp/wiki/Category:PK. PMID:22844193

Food allergy: epidemiology and natural history.

PubMed

Savage, Jessica; Johns, Christina B

2015-02-01

The prevalence of food allergy is rising for unclear reasons, with prevalence estimates in the developed world approaching 10%. Knowledge regarding the natural course of food allergies is important because it can aid the clinician in diagnosing food allergies and in determining when to consider evaluation for food allergy resolution. Many food allergies with onset in early childhood are outgrown later in childhood, although a minority of food allergy persists into adolescence and even adulthood. More research is needed to improve food allergy diagnosis, treatment, and prevention. Copyright © 2015 Elsevier Inc. All rights reserved.

Polyketide synthases from poison hemlock (Conium maculatum L.).

PubMed

Hotti, Hannu; Seppänen-Laakso, Tuulikki; Arvas, Mikko; Teeri, Teemu H; Rischer, Heiko

2015-11-01

Coniine is a toxic alkaloid, the biosynthesis of which is not well understood. A possible route, supported by evidence from labelling experiments, involves a polyketide formed by the condensation of one acetyl-CoA and three malonyl-CoAs catalysed by a polyketide synthase (PKS). We isolated PKS genes or their fragments from poison hemlock (Conium maculatum L.) by using random amplification of cDNA ends (RACE) and transcriptome analysis, and characterized three full-length enzymes by feeding different starter-CoAs in vitro. On the basis of our in vitro experiments, two of the three characterized PKS genes in poison hemlock encode chalcone synthases (CPKS1 and CPKS2), and one encodes a novel type of PKS (CPKS5). We show that CPKS5 kinetically favours butyryl-CoA as a starter-CoA in vitro. Our results suggest that CPKS5 is responsible for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoAs. © 2015 FEBS.

Traces of natural radionuclides in animal food

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merli, Isabella Desan; Guazzelli da Silveira, Marcilei A.; Medina, Nilberto H.

Naturally occurring radioactive materials are present everywhere, e.g., in soil, air, housing materials, food, etc. Therefore, human beings and animals receive internal exposure from radioactive elements inside their bodies through breathing and alimentation. Gamma radiation has enough energy to remove an electron from the atom and compromise the rearrangement of electrons in the search for a more stable configuration which can disturb molecule chemical bonding. Food ingestion is one of the most common forms of radioisotopes absorption. The goal of this work is the measurement of natural gamma radiation rates from natural radioisotopes present in animal food. To determine themore » concentration of natural radionuclides present in animal food gamma-ray spectrometry was applied. We have prepared animal food samples for poultry, fish, dogs, cats and cattle. The two highest total ingestion effective doses observed refers to a sample of mineral salt cattle, 95.3(15) μSv/year, rabbit chow, with a value of 48(5) μSv/year, and cattle mineral salt, with a value of 69(7) μSv/year, while the annual total dose value from terrestrial intake radionuclide is of the order of 290 μSv/year.« less

Traces of natural radionuclides in animal food

NASA Astrophysics Data System (ADS)

Merli, Isabella Desan; da Silveira, Marcilei A. Guazzelli; Medina, Nilberto H.

2014-11-01

Naturally occurring radioactive materials are present everywhere, e.g., in soil, air, housing materials, food, etc. Therefore, human beings and animals receive internal exposure from radioactive elements inside their bodies through breathing and alimentation. Gamma radiation has enough energy to remove an electron from the atom and compromise the rearrangement of electrons in the search for a more stable configuration which can disturb molecule chemical bonding. Food ingestion is one of the most common forms of radioisotopes absorption. The goal of this work is the measurement of natural gamma radiation rates from natural radioisotopes present in animal food. To determine the concentration of natural radionuclides present in animal food gamma-ray spectrometry was applied. We have prepared animal food samples for poultry, fish, dogs, cats and cattle. The two highest total ingestion effective doses observed refers to a sample of mineral salt cattle, 95.3(15) μSv/year, rabbit chow, with a value of 48(5) μSv/year, and cattle mineral salt, with a value of 69(7) μSv/year, while the annual total dose value from terrestrial intake radionuclide is of the order of 290 μSv/year.

Natural pet food: a review of natural diets and their impact on canine and feline physiology.

PubMed

Buff, P R; Carter, R A; Bauer, J E; Kersey, J H

2014-09-01

The purpose of this review is to clarify the definition of "natural" as it pertains to commercial pet food and to summarize the scientific findings related to natural ingredients in pet foods and natural diets on the impact of pet health and physiology. The term "natural," when used to market commercial pet foods or pet food ingredients in the United States, has been defined by the Association of American Feed Control Officials and requires, at minimum, that the pet food be preserved with natural preservatives. However, pet owners may consider natural as something different than the regulatory definition. The natural pet food trend has focused on the inclusion of whole ingredients, including meats, fruits, and vegetables; avoiding ingredients perceived as heavily processed, including refined grains, fiber sources, and byproducts; and feeding according to ancestral or instinctual nutritional philosophies. Current scientific evidence supporting nutritional benefits of natural pet food products is limited to evaluations of dietary macronutrient profiles, fractionation of ingredients, and the processing of ingredients and final product. Domestic cats select a macronutrient profile (52% of ME from protein) similar to the diet of wild cats. Dogs have evolved much differently in their ability to metabolize carbohydrates and select a diet lower in protein (30% of ME from protein) than the diet of wild wolves. The inclusion of whole food ingredients in natural pet foods as opposed to fractionated ingredients may result in higher nutrient concentrations, including phytonutrients. Additionally, the processing of commercial pet food can impact digestibility, nutrient bioavailability, and safety, which are particularly important considerations with new product formats in the natural pet food category. Future opportunities exist to better understand the effect of natural diets on health and nutrition outcomes and to better integrate sustainable practices in the production of

Differential Expression of Putative Polyketide Biosynthetic Gene Clusters in Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

The maize pathogen Fusarium verticillioides can produce a number of polyketide derived secondary metabolites, including fumonisins. Fumonisins cause diseases in animals, and show epidemiological correlation with esophageal cancer and birth defects in humans. The F. verticillioides genome contains ...

Conversion of the high-yield salinomycin producer Streptomyces albus BK3-25 into a surrogate host for polyketide production.

PubMed

Zhang, Xiaojie; Lu, Chenyang; Bai, Linquan

2017-09-01

An ideal surrogate host for heterologous production of various natural products is expected to have efficient nutrient utilization, fast growth, abundant precursors and energy supply, and a pronounced gene expression. Streptomyces albus BK3-25 is a high-yield industrial strain producing type-I polyketide salinomycin, with a unique ability of bean oil utilization. Its potential of being a surrogate host for heterologous production of PKS was engineered and evaluated herein. Firstly, introduction of a three-gene cassette for the biosynthesis of ethylmalonyl-CoA resulted in accumulation of ethylmalonyl-CoA precursor and salinomycin, and subsequent deletion of the salinomycin biosynthetic gene cluster resulted in a host with rich supplies of common polyketide precursors, including malonyl-CoA, methylmalonyl-CoA, and ethylmalonyl-CoA. Secondly, the energy and reducing force were measured, and the improved accumulation of ATP and NADPH was observed in the mutant. Furthermore, the strength of a series of selected endogenous promoters based on microarray data was assessed at different growth phases, and a strong constitutive promoter was identified, providing a useful tool for further engineered gene expression. Finally, the potential of the BK3-25 derived host ZXJ-6 was evaluated with the introduction of the actinorhodin biosynthetic gene cluster from Streptomyces coelicolor, and the heterologous production of actinorhodin was obtained. This work clearly indicated the potential of the high-yield salinomycin producer as a surrogate host for heterologous production of polyketides, although more genetic manipulation should be conducted to streamline its performance.

The Natural History of Food Allergy.

PubMed

Savage, Jessica; Sicherer, Scott; Wood, Robert

2016-01-01

On a population level, it is well recognized that some IgE-mediated childhood food allergies, such as milk and egg allergies, are more likely to resolve than others, such as peanut and tree nuts allergies. Unfortunately, some studies suggest that resolution rates may have slowed compared with impressions from past decades. The clinician can apply the knowledge of the epidemiology of these allergies to describe likely patient outcomes, and direct management in a general manner. However, the ability to evaluate and predict the natural course of specific food allergies for individual patients is essential to inform personalized patient care. Data are accumulating to assist in identifying whether a child's allergy has likely resolved, informing the timing of oral food challenges or subsequent testing. Exciting recent studies are increasingly identifying early prognostic markers as well. Emerging food allergy therapies carry risks and costs. Identifying which egg-allergic patient has likely persistent allergy, and which patient with peanut allergy may experience natural resolution, is becoming an important goal to identify the best candidates for these therapies. Although more work needs to be done to identify reliable predictive markers and validate them, there is already much known about the natural course of food allergies that can be applied by the clinician to improve patient care. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Is eating science or common sense? Knowledge about "natural foods" among self-identified "natural food" consumers, vendors and producers in rural and urban Mexico.

PubMed

Kooijmans, Anneke; Flores-Palacios, Fátima

2014-10-01

To explore the common sense knowledge that consumers, vendors and producers hold of "natural foods". The focus was on common knowledge because this is infrequently explored in social psychology where most studies focus on the implementation of scientific knowledge. The focus was on natural foods because the naturalness of foods seems to be one of the particular concerns that current consumers have about today's food market and because a specific natural food preference was observed in the contexts of study. Fifty-seven informants in a rural context and 58 informants in an urban context participated in either a free association study or an interview study. Data content were analyzed. In the urban context natural foods obtain their significance in the relationship between food and the self-concept; eating natural (or good) food is a task that requires effort and attitude, and foods obtain a moral value. In the rural context natural foods obtain their significance as an expression of a social and cultural system of interdependence that establishes practices and customs that have a long history in the community. It is suggested that these common knowledge systems are related to practical challenges that are particular to the informants' context and that the structure of their common sense knowledge systems depend on the mediation of the flow of scientific knowledge and technological knowledge in each context. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chip-based polyketide biosynthesis and functionalization.

PubMed

Ku, Bosung; Cha, Junhoe; Srinivasan, Aravind; Kwon, Seok Joon; Jeong, Jae-Choel; Sherman, David H; Dordick, Jonathan S

2006-01-01

We demonstrate construction and novel compound synthesis from a synthetic metabolic pathway consisting of a type III polyketide synthase (PKS) known as 1,3,6,8-tetrahydroxynaphthalene synthase (THNS) from Streptomyces coelicolor and soybean peroxidase (SBP) in a microfluidic platform. THNS immobilized to Ni-NTA agarose beads is prepacked into a microfluidic channel, while SBP is covalently attached to the walls of a second microfluidic channel precoated with a reactive poly(maleic anhydride) derivative. The result is a tandem, two-step biochip that enables the synthesis of novel polyketide derivatives. The first microchannel, consisting of THNS, results in the conversion of malonyl-CoA to flaviolin in yields up to 40% with a residence time of 6 min. This conversion is similar to that obtained in several-milliliter batch reactions after 2 h. Linking this microchannel to the SBP microchannel results in biflaviolin synthesis. During the course of this work, we discovered that the substrate specificity of THNS could be manipulated by simply changing the reaction pH. As a result, the starter acyl-CoA specificity can be broadened to yield a series of truncated pyrone products. When combined with variations in the ratio of acyl-CoA and malonyl-CoA (extender substrate) feed rates, high yields of the pyrone products could be achieved, which is further structurally diversified from self- and cross-coupling in the SBP microchannel. The ability to rapidly evaluate the effects of reaction conditions and synthetic multienzyme pathways on a microfludic platform provides a new paradigm for performing metabolic pathway engineering, namely, the reconstruction of pathways for use in new compound discovery.

Atlas of nonribosomal peptide and polyketide biosynthetic pathways reveals common occurrence of nonmodular enzymes.

PubMed

Wang, Hao; Fewer, David P; Holm, Liisa; Rouhiainen, Leo; Sivonen, Kaarina

2014-06-24

Nonribosomal peptides and polyketides are a diverse group of natural products with complex chemical structures and enormous pharmaceutical potential. They are synthesized on modular nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) enzyme complexes by a conserved thiotemplate mechanism. Here, we report the widespread occurrence of NRPS and PKS genetic machinery across the three domains of life with the discovery of 3,339 gene clusters from 991 organisms, by examining a total of 2,699 genomes. These gene clusters display extraordinarily diverse organizations, and a total of 1,147 hybrid NRPS/PKS clusters were found. Surprisingly, 10% of bacterial gene clusters lacked modular organization, and instead catalytic domains were mostly encoded as separate proteins. The finding of common occurrence of nonmodular NRPS differs substantially from the current classification. Sequence analysis indicates that the evolution of NRPS machineries was driven by a combination of common descent and horizontal gene transfer. We identified related siderophore NRPS gene clusters that encoded modular and nonmodular NRPS enzymes organized in a gradient. A higher frequency of the NRPS and PKS gene clusters was detected from bacteria compared with archaea or eukarya. They commonly occurred in the phyla of Proteobacteria, Actinobacteria, Firmicutes, and Cyanobacteria in bacteria and the phylum of Ascomycota in fungi. The majority of these NRPS and PKS gene clusters have unknown end products highlighting the power of genome mining in identifying novel genetic machinery for the biosynthesis of secondary metabolites.

Biosynthetic Potential-Based Strain Prioritization for Natural Product Discovery: A Showcase for Diterpenoid-Producing Actinomycetes

PubMed Central

2015-01-01

Natural products remain the best sources of drugs and drug leads and serve as outstanding small-molecule probes to dissect fundamental biological processes. A great challenge for the natural product community is to discover novel natural products efficiently and cost effectively. Here we report the development of a practical method to survey biosynthetic potential in microorganisms, thereby identifying the most promising strains and prioritizing them for natural product discovery. Central to our approach is the innovative preparation, by a two-tiered PCR method, of a pool of pathway-specific probes, thereby allowing the survey of all variants of the biosynthetic machineries for the targeted class of natural products. The utility of the method was demonstrated by surveying 100 strains, randomly selected from our actinomycete collection, for their biosynthetic potential of four classes of natural products, aromatic polyketides, reduced polyketides, nonribosomal peptides, and diterpenoids, identifying 16 talented strains. One of the talented strains, Streptomyces griseus CB00830, was finally chosen to showcase the discovery of the targeted classes of natural products, resulting in the isolation of three diterpenoids, six nonribosomal peptides and related metabolites, and three polyketides. Variations of this method should be applicable to the discovery of other classes of natural products. PMID:24484381

Natural antioxidant extracts as food preservatives.

PubMed

Santos-Sánchez, Norma F; Salas-Coronado, Raúl; Valadez-Blanco, Rogelio; Hernández-Carlos, Beatriz; Guadarrama-Mendoza, Paula C

2017-01-01

The food industry is becoming more specialized and processing methods are continuously being developed to meet consumer needs. Consumers demand products that are safe and preferably free of synthetic additives. These additives are associated with health effects, in most cases without reasonable justification. Consequently, consumers are looking for clearly labelled products that guarantee the absence of synthetic additives. This has led to the need to search for natural additives, which the food industry claims arenatural antioxidant preservatives. The sources of natural antioxidants can be extremely varied, because practically all plants contain antioxidants that allow them to protect themselves from solar radiation and pests, as well as to regulate the production of chemical energy. However, the best alternatives for the food industry are fruits and spices, because they are already foods themselves. This article will describe fruits and spices considered as important sources of phenolic antioxidants. The main medicinal properties are related to phenolic compounds and their uses as additives, depending on their chemical structure.

A novel polyketide biosynthesis gene cluster is involved in fruiting body morphogenesis in the filamentous fungi Sordaria macrospora and Neurospora crassa.

PubMed

Nowrousian, Minou

2009-04-01

During fungal fruiting body development, hyphae aggregate to form multicellular structures that protect and disperse the sexual spores. Analysis of microarray data revealed a gene cluster strongly upregulated during fruiting body development in the ascomycete Sordaria macrospora. Real time PCR analysis showed that the genes from the orthologous cluster in Neurospora crassa are also upregulated during development. The cluster encodes putative polyketide biosynthesis enzymes, including a reducing polyketide synthase. Analysis of knockout strains of a predicted dehydrogenase gene from the cluster showed that mutants in N. crassa and S. macrospora are delayed in fruiting body formation. In addition to the upregulated cluster, the N. crassa genome comprises another cluster containing a polyketide synthase gene, and five additional reducing polyketide synthase (rpks) genes that are not part of clusters. To study the role of these genes in sexual development, expression of the predicted rpks genes in S. macrospora (five genes) and N. crassa (six genes) was analyzed; all but one are upregulated during sexual development. Analysis of knockout strains for the N. crassa rpks genes showed that one of them is essential for fruiting body formation. These data indicate that polyketides produced by RPKSs are involved in sexual development in filamentous ascomycetes.

Recognition of Acyl Carrier Proteins by Ketoreductases in Assembly Line Polyketide Synthases

PubMed Central

Ostrowski, Matthew P.; Cane, David E.; Khosla, Chaitan

2016-01-01

Ketoreductases (KRs) are the most widespread tailoring domains found in individual modules of assembly line polyketide synthases (PKSs), and are responsible for controlling the configurations of both the α-methyl and β-hydroxyl stereogenic centers in the growing polyketide chain. Because they recognize substrates that are covalently bound to acyl carrier proteins (ACPs) within the same PKS module, we sought to quantify the extent to which protein-protein recognition contributes to the turnover of these oxidoreductive enzymes using stand-alone domains from the 6-deoxyerythronolide B synthase (DEBS). Reduced 2-methyl-3-hydroxyacyl-ACP substrates derived from two enantiomeric acyl chains and four distinct ACP domains were synthesized and presented to four distinct KR domains. Two KRs, from DEBS modules 2 and 5, displayed little preference for oxidation of substrates tethered to their cognate ACP domains over those attached to the other ACP domains tested. In contrast, the KR from DEBS module 1 showed a ca. 10-50-fold preference for substrate attached to its native ACP domain, whereas the KR from DEBS module 6 actually displayed a ca. 10-fold preference for the ACP from DEBS module 5. Our findings suggest that recognition of the ACP by a KR domain is unlikely to affect the rate of native assembly line polyketide biosynthesis. In some cases, however, unfavorable KR-ACP interactions may suppress the rate of substrate processing when KR domains are swapped to construct hybrid PKS modules. PMID:27118242

Sustainable Food Processing Inspired by Nature.

PubMed

Sybesma, Wilbert; Blank, Imre; Lee, Yuan-Kun

2017-04-01

Here, we elaborate on the natural origin and use of enzymes and cultures in sustainable food processing. We also illustrate how enzymatically treated or fermented food can contribute to solving challenges involving nutrition and health, such as aging, malnutrition, obesity, and allergy. Copyright © 2017. Published by Elsevier Ltd.

Emotional faces influence evaluation of natural and transformed food.

PubMed

Manippa, Valerio; Padulo, Caterina; Brancucci, Alfredo

2018-07-01

Previous evidence showed the presence of a straight relationship between feeding behavior and emotions. Despite that, no studies have focused on the influence of emotional faces on food processing. In our study, participants were presented with 72 couples of visual stimuli composed of a neutral, happy, or disgusted faces (5000 ms duration in Experiment 1, adaptation; 150 ms in Experiment 2, priming) followed by a food stimulus (1500 ms). Food stimuli were grouped in pleasant foods, further divided in natural and transformed, and unpleasant rotten foods. The task consisted in judging the food valence (as 'pleasant' or 'unpleasant') by keypress. Results showed a different pattern of response based on the transformation level of food. In general, the evaluation of natural foods was more rapid compared with transformed foods, maybe for their simplicity and healthier perception. In addition, transformed foods yielded incongruent responses with respect to the preceding emotional face, whereas natural foods yielded congruent responses with respect to it. These effects were independent of the duration of the emotional face (i.e., adaptation or priming paradigm) and may depend on pleasant food stimuli salience.

Nonthmicin, a Polyether Polyketide Bearing a Halogen-Modified Tetronate with Neuroprotective and Antiinvasive Activity from Actinomadura sp.

PubMed

Igarashi, Yasuhiro; Matsuoka, Noriaki; In, Yasuko; Kataura, Tetsushi; Tashiro, Etsu; Saiki, Ikuo; Sudoh, Yuri; Duangmal, Kannika; Thamchaipenet, Arinthip

2017-03-17

Nonthmicin (1), a new polyether polyketide bearing a chlorinated tetronic acid, was isolated from the culture extract of a soil-derived Actinomadura strain. The structure of 1 was elucidated by interpretation of NMR and MS spectroscopic data, and the absolute configuration of 1 was proposed on the basis of the crystal structure of its dechloro congener ecteinamycin (2) also isolated from the same strain. Tetronic acids modified by halogenation have never been reported from natural products. Compounds 1 and 2 were found to have neuroprotective activity and antimetastatic properties at submicromolar concentrations in addition to antibacterial activity.

Kernel based machine learning algorithm for the efficient prediction of type III polyketide synthase family of proteins.

PubMed

Mallika, V; Sivakumar, K C; Jaichand, S; Soniya, E V

2010-07-13

Type III Polyketide synthases (PKS) are family of proteins considered to have significant roles in the biosynthesis of various polyketides in plants, fungi and bacteria. As these proteins shows positive effects to human health, more researches are going on regarding this particular protein. Developing a tool to identify the probability of sequence being a type III polyketide synthase will minimize the time consumption and manpower efforts. In this approach, we have designed and implemented PKSIIIpred, a high performance prediction server for type III PKS where the classifier is Support Vector Machines (SVMs). Based on the limited training dataset, the tool efficiently predicts the type III PKS superfamily of proteins with high sensitivity and specificity. The PKSIIIpred is available at http://type3pks.in/prediction/. We expect that this tool may serve as a useful resource for type III PKS researchers. Currently work is being progressed for further betterment of prediction accuracy by including more sequence features in the training dataset.

Implication of PKS type I gene and chromatographic strategy for the biodiscovery of antimicrobial polyketide metabolites from endosymbiotic Nocardiopsis prasina CLA68

NASA Astrophysics Data System (ADS)

Rao, H. C. Yashavantha; Rakshith, Devaraju; Gurudatt, D. M.; Satish, Sreedharamurthy

2016-06-01

Advanced approach in probing for polyketide antimicrobials requires novel genomics and chromatographic strategies. An endophytic strain CLA68 was isolated from the root of Combretum latifolium Blume (Combretaceae) collected from the Western Ghats of Southern India. Strain CLA68 was then identified as Nocardiopsis prasina by its characteristic culture morphology and analysis of 16S rRNA gene sequence. Biosynthetic polyketide synthase genes were investigated using two pairs of degenerate primers. Ethyl acetate extract of CLA68 exhibited broad spectrum activity against a panel of test human pathogens. PKS type-I gene detection and chromatographic strategy yielded a robust polyketide antimicrobial compound which identified as nocapyrone E. Minimum inhibitory concentration of the purified compound against MRSA and other human pathogens ranged between 25 and 100 μg/ml. The present work highlights the utility of N. prasina CLA68 as potential source for antimicrobial polyketide nocapyrone E which could help to combat multidrug-resistant pathogens. This study demonstrates feasibility of PKS type-I gene-based molecular approach and chemical investigation by chromatographic approach is the best method for prediction and rapid discovery of novel polyketides from endosymbiotic actinomycetes. The sequence data of this endosymbiotic actinomycete is deposited in GenBank under the accession no. KP269077.

An overview of natural antimicrobials role in food.

PubMed

Pisoschi, Aurelia Magdalena; Pop, Aneta; Georgescu, Cecilia; Turcuş, Violeta; Olah, Neli Kinga; Mathe, Endre

2018-01-01

The present paper aims to review the natural food preservatives with antimicrobial properties emphasizing their importance for the future of food manufacturing and consumers' health. The extraction procedures applied to natural antimicrobials will be considered, followed by the description of some natural preservatives' antimicrobial mechanism of action, including (i) membrane rupture with ATP-ase activity inhibition, (ii) leakage of essential biomolecules from the cell, (iii) disruption of the proton motive force and (iiii) enzyme inactivation. Moreover, a provenance-based classification of natural antimicrobials is discussed by considering the sources of origin for the major natural preservative categories: plants, animals, microbes and fungi. As well, the structure influence on the antimicrobial potential is considered. Natural preservatives could also constitute a viable alternative to address the critical problem of microbial resistance, and to hamper the negative side effects of some synthetic compounds, while meeting the requirements for food safety, and exerting no negative impact on nutritional and sensory attributes of foodstuffs. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Crystallization and preliminary crystallographic analysis of an acridone-producing novel multifunctional type III polyketide synthase from Huperzia serrata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morita, Hiroyuki; Kondo, Shin; Kato, Ryohei

2007-07-01

An acridone-producing novel type III polyketide synthase from H. serrata has been overexpressed in E. coli, purified and crystallized. Diffraction data have been collected to 2.0 Å. Polyketide synthase 1 (PKS1) from Huperzia serrata is a plant-specific type III polyketide synthase that shows an unusually versatile catalytic potential, producing various aromatic tetraketides, including chalcones, benzophenones, phlorogulucinols and acridones. Recombinant H. serrata PKS1 expressed in Escherichia coli was crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to space group I222 or I2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 73.3, b = 85.0, c = 137.7 Å, α =more » β = γ = 90.0°. Diffraction data were collected to 2.0 Å resolution using synchrotron radiation at BL24XU of SPring-8.« less

Natural biopolimers in organic food packaging

NASA Astrophysics Data System (ADS)

Wieczynska, Justyna; Cavoski, Ivana; Chami, Ziad Al; Mondelli, Donato; Di Donato, Paola; Di Terlizzi, Biagio

2014-05-01

Concerns on environmental and waste problems caused by use of non-biodegradable and non-renewable based plastic packaging have caused an increase interest in developing biodegradable packaging using renewable natural biopolymers. Recently, different types of biopolymers like starch, cellulose, chitosan, casein, whey protein, collagen, egg white, soybean protein, corn zein, gelatin and wheat gluten have attracted considerable attention as potential food packaging materials. Recyclable or biodegradable packaging material in organic processing standards is preferable where possible but specific principles of packaging are not precisely defined and standards have to be assessed. There is evidence that consumers of organic products have specific expectations not only with respect to quality characteristics of processed food but also in social and environmental aspects of food production. Growing consumer sophistication is leading to a proliferation in food eco-label like carbon footprint. Biopolymers based packaging for organic products can help to create a green industry. Moreover, biopolymers can be appropriate materials for the development of an active surfaces designed to deliver incorporated natural antimicrobials into environment surrounding packaged food. Active packaging is an innovative mode of packaging in which the product and the environment interact to prolong shelf life or enhance safety or sensory properties, while maintaining the quality of the product. The work will discuss the various techniques that have been used for development of an active antimicrobial biodegradable packaging materials focusing on a recent findings in research studies. With the current focus on exploring a new generation of biopolymer-based food packaging materials with possible applications in organic food packaging. Keywords: organic food, active packaging, biopolymers , green technology

Producing a trimethylpentanoic acid using hybrid polyketide synthases

DOEpatents

Katz, Leonard; Fortman, Jeffrey L; Keasling, Jay D

2014-10-07

The present invention provides for a polyketide synthase (PKS) capable of synthesizing trimethylpentanoic acid. The present invention also provides for a host cell comprising the PKS and when cultured produces the trimethylpentanoic acid. The present invention also provides for a method of producing the trimethylpentanoic acid, comprising: providing a host cell of the present invention, and culturing said host cell in a suitable culture medium such that the trimethylpentanoic acid is produced, optionally isolating the trimethylpentanoic acid, and optionally, reducing the isolated trimethylpentanoic acid into a trimethylpentanol or an iso-octane.

Expanding the chemical diversity of natural esters by engineering a polyketide-derived pathway into Escherichia coli.

PubMed

Menendez-Bravo, Simón; Comba, Santiago; Sabatini, Martín; Arabolaza, Ana; Gramajo, Hugo

2014-07-01

Microbial fatty acid (FA)-derived molecules have emerged as promising alternatives to petroleum-based chemicals for reducing dependence on fossil hydrocarbons. However, native FA biosynthetic pathways often yield limited structural diversity, and therefore restricted physicochemical properties, of the end products by providing only a limited variety of usually linear hydrocarbons. Here we have engineered into Escherichia coli a mycocerosic polyketide synthase-based biosynthetic pathway from Mycobacterium tuberculosis and redefined its biological role towards the production of multi-methyl-branched-esters (MBEs) with novel chemical structures. Expression of FadD28, Mas and PapA5 enzymes enabled the biosynthesis of multi-methyl-branched-FA and their further esterification to an alcohol. The high substrate tolerance of these enzymes towards different FA and alcohol moieties resulted in the biosynthesis of a broad range of MBE. Further metabolic engineering of the MBE producer strain coupled this system to long-chain-alcohol biosynthetic pathways resulting in de novo production of branched wax esters following addition of only propionate. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Polyketides from Pestalotiopsis zonata and structure revision of pestalrones A and B.

PubMed

Xu, Xin; Liu, Chang; Dong, Ya-Jing; Liu, Fang-Ru; Xu, Xiu-Mei; Li, De-Sheng; Li, Dan-Yi; Li, Zhan-Lin

2017-11-23

The structures of pestalrones A-B were revised via reinterpretation of the NMR data and a brief chemical transformation from the co-occurring polyketides, in our investigation on the secondary metabolites of Pestalotiopsis zonata, which also afforded a new α-pyrone derivative, pestazonatic acid, and four known analogs.

Functional analysis of environmental DNA-derived type II polyketide synthases reveals structurally diverse secondary metabolites.

PubMed

Feng, Zhiyang; Kallifidas, Dimitris; Brady, Sean F

2011-08-02

A single gram of soil is predicted to contain thousands of unique bacterial species. The majority of these species remain recalcitrant to standard culture methods, prohibiting their use as sources of unique bioactive small molecules. The cloning and analysis of DNA extracted directly from environmental samples (environmental DNA, eDNA) provides a means of exploring the biosynthetic capacity of natural bacterial populations. Environmental DNA libraries contain large reservoirs of bacterial genetic diversity from which new secondary metabolite gene clusters can be systematically recovered and studied. The identification and heterologous expression of type II polyketide synthase-containing eDNA clones is reported here. Functional analysis of three soil DNA-derived polyketide synthase systems in Streptomyces albus revealed diverse metabolites belonging to well-known, rare, and previously uncharacterized structural families. The first of these systems is predicted to encode the production of the known antibiotic landomycin E. The second was found to encode the production of a metabolite with a previously uncharacterized pentacyclic ring system. The third was found to encode the production of unique KB-3346-5 derivatives, which show activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. These results, together with those of other small-molecule-directed metagenomic studies, suggest that culture-independent approaches are capable of accessing biosynthetic diversity that has not yet been extensively explored using culture-based methods. The large-scale functional screening of eDNA clones should be a productive strategy for generating structurally previously uncharacterized chemical entities for use in future drug development efforts.

Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources

PubMed Central

Xu, Dong-Ping; Li, Ya; Meng, Xiao; Zhou, Tong; Zhou, Yue; Zheng, Jie; Zhang, Jiao-Jiao; Li, Hua-Bin

2017-01-01

Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants. PMID:28067795

Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources.

PubMed

Xu, Dong-Ping; Li, Ya; Meng, Xiao; Zhou, Tong; Zhou, Yue; Zheng, Jie; Zhang, Jiao-Jiao; Li, Hua-Bin

2017-01-05

Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants.

Synergistic Cytotoxicity Effect by Combination Treatment of Polyketide Derivatives from Annona muricata Linn Leaves and Doxorubicin as Potential Anticancer Material on Raji Cell Line

NASA Astrophysics Data System (ADS)

Artanti, A. N.; Astirin, O. P.; Prayito, A.; Fisma, R.; Prihapsara, F.

2018-03-01

Nasopharynx cancer is one of the most deadly cancer. The main priority of nasopharynx cancer treatment is the use of chemotherapeutic agents, especially doxorubicin. However, doxorubicin might also lead to diverse side effect. An approach recently develop to overcome side effect of doxorubicin is to used of combined chemotherapeutic agent. One of the compounds found effication as an anticancer agent on nasopharynx cancer is acetogenin, a polyketide compound that is abundant in Annona muricata L. leaves. This study has been done to examine polyketide derivatives was isolated from Annona muricata L. which has potency to induce apoptosis by p53 expression on raji cell line. The determination of cytotoxic combination activity from polyketide derivative and doxorubicin was evaluated using MTT assay to obtain the value of CI (combination index). Data analysis showed that combination of polyketide derivative from Annona muricata L. (14,4 µg/ml) and doxorubicin with all of concentration performed synergistic effect on raji cell line with CI value from 0.13 – 0.65.

Natural history of food protein-induced enterocolitis syndrome.

PubMed

Katz, Yitzhak; Goldberg, Michael R

2014-06-01

Because of the paucity of reports and variability in the diagnostic criteria utilized, little is known regarding the natural outcome of patients with food protein-induced enterocolitis syndrome (FPIES). Data extracted from referenced manuscripts, as well as allergists' unpublished observations from across the globe, were used to form a cohesive opinion regarding its natural outcome. All authors concur that there is a generally high rate of recovery for FPIES. The most common foods causing FPIES are milk and soy. Depending upon which study is analyzed, by the age of 3-5 years, approximately 90% of patients recover from their disease. Recovery from FPIES to solid foods, occurs at a later age, but may reflect a later stage of introduction of the food into the diet. An important clinical outcome, although not common, is a shift from FPIES food hypersensitivity to an IgE-mediated food allergy. This necessitates a change in the oral food challenge protocol, if IgE-mediated sensitization is detected. Over the past several years, there has been an increasing awareness of FPIES. This knowledge should lead to a more timely diagnosis and should reassure parents and practitioners alike regarding its favorable course.

Natural Phenol Polymers: Recent Advances in Food and Health Applications.

PubMed

Panzella, Lucia; Napolitano, Alessandra

2017-04-14

Natural phenol polymers are widely represented in nature and include a variety of classes including tannins and lignins as the most prominent. Largely consumed foods are rich sources of phenol polymers, notably black foods traditionally used in East Asia, but other non-edible, easily accessible sources, e.g., seaweeds and wood, have been considered with increasing interest together with waste materials from agro-based industries, primarily grape pomace and other byproducts of fruit and coffee processing. Not in all cases were the main structural components of these materials identified because of their highly heterogeneous nature. The great beneficial effects of natural phenol-based polymers on human health and their potential in improving the quality of food were largely explored, and this review critically addresses the most interesting and innovative reports in the field of nutrition and biomedicine that have appeared in the last five years. Several in vivo human and animal trials supported the proposed use of these materials as food supplements and for amelioration of the health and production of livestock. Biocompatible and stable functional polymers prepared by peroxidase-catalyzed polymerization of natural phenols, as well as natural phenol polymers were exploited as conventional and green plastic additives in smart packaging and food-spoilage prevention applications. The potential of natural phenol polymers in regenerative biomedicine as additives of biomaterials to promote growth and differentiation of osteoblasts is also discussed.

Pseudomonas syringae Phytotoxins: Mode of Action, Regulation, and Biosynthesis by Peptide and Polyketide Synthetases

PubMed Central

Bender, Carol L.; Alarcón-Chaidez, Francisco; Gross, Dennis C.

1999-01-01

Coronatine, syringomycin, syringopeptin, tabtoxin, and phaseolotoxin are the most intensively studied phytotoxins of Pseudomonas syringae, and each contributes significantly to bacterial virulence in plants. Coronatine functions partly as a mimic of methyl jasmonate, a hormone synthesized by plants undergoing biological stress. Syringomycin and syringopeptin form pores in plasma membranes, a process that leads to electrolyte leakage. Tabtoxin and phaseolotoxin are strongly antimicrobial and function by inhibiting glutamine synthetase and ornithine carbamoyltransferase, respectively. Genetic analysis has revealed the mechanisms responsible for toxin biosynthesis. Coronatine biosynthesis requires the cooperation of polyketide and peptide synthetases for the assembly of the coronafacic and coronamic acid moieties, respectively. Tabtoxin is derived from the lysine biosynthetic pathway, whereas syringomycin, syringopeptin, and phaseolotoxin biosynthesis requires peptide synthetases. Activation of phytotoxin synthesis is controlled by diverse environmental factors including plant signal molecules and temperature. Genes involved in the regulation of phytotoxin synthesis have been located within the coronatine and syringomycin gene clusters; however, additional regulatory genes are required for the synthesis of these and other phytotoxins. Global regulatory genes such as gacS modulate phytotoxin production in certain pathovars, indicating the complexity of the regulatory circuits controlling phytotoxin synthesis. The coronatine and syringomycin gene clusters have been intensively characterized and show potential for constructing modified polyketides and peptides. Genetic reprogramming of peptide and polyketide synthetases has been successful, and portions of the coronatine and syringomycin gene clusters could be valuable resources in developing new antimicrobial agents. PMID:10357851

A dual role for a polyketide synthase in dynemicin enediyne and anthraquinone biosynthesis

NASA Astrophysics Data System (ADS)

Cohen, Douglas R.; Townsend, Craig A.

2018-02-01

Dynemicin A is a member of a subfamily of enediyne antitumour antibiotics characterized by a 10-membered carbocycle fused to an anthraquinone, both of polyketide origin. Sequencing of the dynemicin biosynthetic gene cluster in Micromonospora chersina previously identified an enediyne polyketide synthase (PKS), but no anthraquinone PKS, suggesting gene(s) for biosynthesis of the latter were distant from the core dynemicin cluster. To identify these gene(s), we sequenced and analysed the genome of M. chersina. Sequencing produced a short list of putative PKS candidates, yet CRISPR-Cas9 mutants of each locus retained dynemicin production. Subsequently, deletion of two cytochromes P450 in the dynemicin cluster suggested that the dynemicin enediyne PKS, DynE8, may biosynthesize the anthraquinone. Together with 18O-labelling studies, we now present evidence that DynE8 produces the core scaffolds of both the enediyne and anthraquinone, and provide a working model to account for their formation from the programmed octaketide of the enediyne PKS.

Crystallization and preliminary X-ray diffraction studies of polyketide synthase-1 (PKS-1) from Cannabis sativa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taguchi, Chiho; Quantum Beam Science Directorate, Japan Atomic Energy Agency; Taura, Futoshi

Polyketide synthase-1 from C. sativa has been crystallized. The crystal diffracted to 1.55 Å resolution with sufficient quality for further structure determination. Polyketide synthase-1 (PKS-1) is a novel type III polyketide synthase that catalyzes the biosynthesis of hexanoyl triacetic acid lactone in Cannabis sativa (Mexican strain). PKS-1 was overproduced in Escherichia coli, purified and finally crystallized in two different space groups. The crystal obtained in 0.1 M HEPES buffer pH 7.5 containing 0.2 M calcium acetate and 20%(w/v) polyethylene glycol 3350 diffracted to 1.65 Å resolution and belonged to space group P1, with unit-cell parameters a = 54.3, b =more » 59.3, c = 62.6 Å, α = 69, β = 81, γ = 80°. Another crystal obtained in 0.1 M HEPES buffer pH 7.5 containing 0.2 M sodium chloride and 20%(w/v) polyethylene glycol 3350 diffracted to 1.55 Å resolution and belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 54.3, b = 110, c = 130 Å. These data will enable us to determine the crystal structure of PKS-1.« less

Altered expression of polyketide biosynthetic gene clusters in fumonisin-deficient mutants of Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a pathogen of maize and produces fumonisins, a group of polyketide derived secondary metabolites. Fumonisins cause diseases in animals, and they have been correlated epidemiologically with esophageal cancer and birth defects in humans. Fumonisin biosynthetic genes are c...

Natural Phenol Polymers: Recent Advances in Food and Health Applications

PubMed Central

Panzella, Lucia; Napolitano, Alessandra

2017-01-01

Natural phenol polymers are widely represented in nature and include a variety of classes including tannins and lignins as the most prominent. Largely consumed foods are rich sources of phenol polymers, notably black foods traditionally used in East Asia, but other non-edible, easily accessible sources, e.g., seaweeds and wood, have been considered with increasing interest together with waste materials from agro-based industries, primarily grape pomace and other byproducts of fruit and coffee processing. Not in all cases were the main structural components of these materials identified because of their highly heterogeneous nature. The great beneficial effects of natural phenol-based polymers on human health and their potential in improving the quality of food were largely explored, and this review critically addresses the most interesting and innovative reports in the field of nutrition and biomedicine that have appeared in the last five years. Several in vivo human and animal trials supported the proposed use of these materials as food supplements and for amelioration of the health and production of livestock. Biocompatible and stable functional polymers prepared by peroxidase-catalyzed polymerization of natural phenols, as well as natural phenol polymers were exploited as conventional and green plastic additives in smart packaging and food-spoilage prevention applications. The potential of natural phenol polymers in regenerative biomedicine as additives of biomaterials to promote growth and differentiation of osteoblasts is also discussed. PMID:28420078

Genomes to natural products PRediction Informatics for Secondary Metabolomes (PRISM)

PubMed Central

Skinnider, Michael A.; Dejong, Chris A.; Rees, Philip N.; Johnston, Chad W.; Li, Haoxin; Webster, Andrew L. H.; Wyatt, Morgan A.; Magarvey, Nathan A.

2015-01-01

Microbial natural products are an invaluable source of evolved bioactive small molecules and pharmaceutical agents. Next-generation and metagenomic sequencing indicates untapped genomic potential, yet high rediscovery rates of known metabolites increasingly frustrate conventional natural product screening programs. New methods to connect biosynthetic gene clusters to novel chemical scaffolds are therefore critical to enable the targeted discovery of genetically encoded natural products. Here, we present PRISM, a computational resource for the identification of biosynthetic gene clusters, prediction of genetically encoded nonribosomal peptides and type I and II polyketides, and bio- and cheminformatic dereplication of known natural products. PRISM implements novel algorithms which render it uniquely capable of predicting type II polyketides, deoxygenated sugars, and starter units, making it a comprehensive genome-guided chemical structure prediction engine. A library of 57 tailoring reactions is leveraged for combinatorial scaffold library generation when multiple potential substrates are consistent with biosynthetic logic. We compare the accuracy of PRISM to existing genomic analysis platforms. PRISM is an open-source, user-friendly web application available at http://magarveylab.ca/prism/. PMID:26442528

[Pseudoallergic reactions. Intolerance to natural and synthetic food constituents masquerading as food allergy].

PubMed

Kurek, M

1996-09-01

Adverse hypersensitivity reactions to natural foods and certain drugs and food additives are mediated by immunological (allergy) or non-immunological mechanisms. Some clinical and physiological similarities have been noted between these allergic and non-allergic reactions. This observation has led to the concept of "pseudoallergic reactions-PAR". PAR can be triggered in various ways such as: interactions with the central or peripherical nervous system, non-specific release of mediators, enzyme inhibition due to hereditary or pharmacologically induced enzyme deficiencies and pharmacological properties of some natural food constituents such as biogenic amines. The prevalence of adverse reactions to food additives has been calculated to be about 0.1%. PAR to food additives occurs frequently in patients suffering from urticaria, asthma and may be accompanied by history of aspirin or NSAI pseudoallergic reactions. The same additives (azo dyes, sulphites, benzoates) are used in various drug formulations and may be responsible for eliciting PAR. In Poland, labelling of food additives, following the "E number system", has been mandatory since 1993. Unfortunately, this satisfactory trend has not yet been applied to drug additives. The diagnosis of PAR to food additives is based on the anamnesis with analysis of the patient's drug and dietary intake. Skin tests and "in vitro" tests are only sporadically informative. In each individual patient, a specific challenge with additives is desirable. Food additives may be tested according to the schedule based on DBPCFC principle. Individually performed exclusion regimes are the principal methods of prevention.

Salt reduction in foods using naturally brewed soy sauce.

PubMed

Kremer, Stefanie; Mojet, Jozina; Shimojo, Ryo

2009-08-01

In recent years, health concerns related to salt/sodium chloride consumption have caused an increased demand for salt-reduced foods. Consequently, sodium chloride (NaCl) reduction in foods has become an important challenge. The more so, since a decrease in NaCl content is often reported to be associated with a decrease in consumer acceptance. The objective of the present study was to investigate whether or not it would be possible to reduce the NaCl content in standard Western European foods by replacing it with naturally brewed soy sauce. Three types of foods were investigated: salad dressing (n = 56), soup (n = 52), and stir-fried pork (n = 57). In the 1st step, an exchange rate (ER) by which NaCl can be replaced with soy sauce without a significant change in the overall taste intensity was established per product type, by means of alternative forced choice tests. In the 2nd step, the same consumers evaluated 5 samples per product type with varying NaCl and/or soy sauce content on pleasantness and several sensory attributes. The results showed that it was possible to achieve a NaCl reduction in the tested foods of, respectively, 50%, 17%, and 29% without leading to significant losses in either overall taste intensity or product pleasantness. These results suggest that it is possible to replace NaCl in foods with naturally brewed soy sauce without lowering the overall taste intensity and to reduce the total NaCl content in these foods without decreasing their consumer acceptance. Health concerns related to salt consumption cause an increased demand for salt-reduced foods. Consequently, the development of foods with reduced salt content without decreasing the consumer acceptance is an important challenge for the food industry. A new possible salt reduction approach is described in the present article: The replacement of salt with naturally brewed soy sauce.

Human contact imagined during the production process increases food naturalness perceptions.

PubMed

Abouab, Nathalie; Gomez, Pierrick

2015-08-01

It is well established that food processing and naturalness are not good friends, but is food processing always detrimental to naturalness? Building on the contagion principle, this research examines how production mode (handmade vs. machine-made) influences naturalness perceptions. In a pilot study (n = 69) and an experiment (n = 133), we found that compared with both a baseline condition and a condition in which the mode of production process was portrayed as machine-made, a handmade production mode increases naturalness ratings of a grape juice. A mediation analysis demonstrates that these effects result from higher perceived human contact suggesting that the production process may preserve food naturalness when humanized. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fumonisin-nonproducing mutants exhibit differential expression of putative polyketide biosynthetic gene clusters in Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

The maize pathogen Fusarium verticillioides produces a group of polyketide derived secondary metabolites called fumonisins. Fumonisins can cause diseases in animals, and have been correlated epidemiologically with esophageal cancer and birth defects in humans. The fumonisin biosynthetic gene clust...

Chemogenomics driven discovery of endogenous polyketide anti-infective compounds from endosymbiotic Emericella variecolor CLB38 and their RNA secondary structure analysis

PubMed Central

Yashavantha Rao, H. C.; Rakshith, Devaraju; Harini, Ballagere Puttaraju; Gurudatt, Doddahosuru Mahadevappa; Satish, Sreedharamurthy

2017-01-01

In the postgenomic era, a new strategy for chemical dereplication of polyketide anti-infective drugs requires novel genomics and chromatographic strategies. An endosymbiotic fungal strain CLB38 was isolated from the root tissue of Combretum latifolium Blume (Combretaceae) which was collected from the Western Ghats of India. The isolate CLB38 was then identified as Emericella variecolor by its characteristic stellate ascospores culture morphology and molecular analysis of ITS nuclear rDNA and intervening 5.8S rRNA gene sequence. ITS2 RNA secondary structure modeling clearly distinguished fungal endosymbiont E. variecolor CLB38 with other lifestyles in the same monophyletic clade. Ethyl acetate fraction of CLB38 explored a broad spectrum of antimicrobial activity against multidrug resistant pathogens. Biosynthetic PKS type-I gene and chromatographic approach afford two polyketide antimicrobial compounds which identified as evariquinone and isoindolones derivative emerimidine A. MIC of purified compounds against test microorganisms ranged between 3.12 μg/ml and 12.5 μg/ml. This research highlights the utility of E. variecolor CLB38 as an anticipate source for anti-infective polyketide metabolites evariquinone and emerimidine A to combat multidrug resistant microorganisms. Here we demonstrates a chemogenomics strategy via the feasibility of PKS type-I gene and chromatographic approach as a proficient method for the rapid prediction and discovery of new polyketides compounds from fungal endosymbionts. PMID:28245269

Multimodular biocatalysts for natural product assembly

NASA Astrophysics Data System (ADS)

Schwarzer, Dirk; Marahiel, Mohamed A.

2001-03-01

Nonribosomal peptides and polyketides represent a large class of natural products that show an extreme structural diversity and broad pharmacological relevance. They are synthesized from simple building blocks such as amino or carboxy acids and malonate derivatives on multimodular enzymes called nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), respectively. Although utilizing different substrates, NRPSs and PKSs show striking similarities in the modular architecture of their catalytic domains and product assembly-line mechanism. Among these compounds are well known antibiotics (penicillin, vancomycin and erythromycin) as well as potent immunosuppressive agents (cyclosporin, rapamycin and FK 506). This review focuses on the modular organization of NRPSs, PKSs and mixed NRPS/PKS systems and how modules and domains that build up the biosynthetic templates can be exploited for the rational design of recombinant enzymes capable of synthesizing novel compounds.

The Polyketide Synthase Gene pks4 of Trichoderma reesei Provides Pigmentation and Stress Resistance

PubMed Central

Atanasova, Lea; Knox, Benjamin P.; Kubicek, Christian P.; Baker, Scott E.

2013-01-01

Species of the fungal genus Trichoderma (Hypocreales, Ascomycota) are well-known for their production of various secondary metabolites. Nonribosomal peptides and polyketides represent a major portion of these products. In a recent phylogenomic investigation of Trichoderma polyketide synthase (PKS)-encoding genes, the pks4 from T. reesei was shown to be an orthologue of pigment-forming PKSs involved in synthesis of aurofusarin and bikaverin in Fusarium spp. In this study, we show that deletion of this gene in T. reesei results in loss of green conidial pigmentation and in pigmentation alteration of teleomorph structures. It also has an impact on conidial cell wall stability and the antagonistic abilities of T. reesei against other fungi, including formation of inhibitory metabolites. In addition, deletion of pks4 significantly influences the expression of other PKS-encoding genes of T. reesei. To our knowledge, this is the first indication that a low-molecular-weight pigment-forming PKS is involved in defense, mechanical stability, and stress resistance in fungi. PMID:24036343

Trends in the use of natural antioxidants in active food packaging: a review.

PubMed

Sanches-Silva, Ana; Costa, Denise; Albuquerque, Tânia G; Buonocore, Giovanna Giuliana; Ramos, Fernando; Castilho, Maria Conceição; Machado, Ana Vera; Costa, Helena S

2014-01-01

The demand for natural antioxidant active packaging is increasing due to its unquestionable advantages compared with the addition of antioxidants directly to the food. Therefore, the search for antioxidants perceived as natural, namely those that naturally occur in herbs and spices, is a field attracting great interest. In line with this, in the last few years, natural antioxidants such as α-tocopherol, caffeic acid, catechin, quercetin, carvacrol and plant extracts (e.g. rosemary extract) have been incorporated into food packaging. On the other hand, consumers and the food industry are also interested in active biodegradable/compostable packaging and edible films to reduce environmental impact, minimise food loss and minimise contaminants from industrial production and reutilisation by-products. The present review focuses on the natural antioxidants already applied in active food packaging, and it reviews the methods used to determine the oxidation protection effect of antioxidant active films and the methods used to quantify natural antioxidants in food matrices or food simulants. Lastly consumers' demands and industry trends are also addressed.

Functional Analysis of the Polyketide Synthase Genes in the Filamentous Fungus Gibberella zeae (Anamorph Fusarium graminearum)

PubMed Central

Gaffoor, Iffa; Brown, Daren W.; Plattner, Ron; Proctor, Robert H.; Qi, Weihong; Trail, Frances

2005-01-01

Polyketides are a class of secondary metabolites that exhibit a vast diversity of form and function. In fungi, these compounds are produced by large, multidomain enzymes classified as type I polyketide synthases (PKSs). In this study we identified and functionally disrupted 15 PKS genes from the genome of the filamentous fungus Gibberella zeae. Five of these genes are responsible for producing the mycotoxins zearalenone, aurofusarin, and fusarin C and the black perithecial pigment. A comprehensive expression analysis of the 15 genes revealed diverse expression patterns during grain colonization, plant colonization, sexual development, and mycelial growth. Expression of one of the PKS genes was not detected under any of 18 conditions tested. This is the first study to genetically characterize a complete set of PKS genes from a single organism. PMID:16278459

Essential oils as natural food antimicrobial agents: a review.

PubMed

Vergis, Jess; Gokulakrishnan, P; Agarwal, R K; Kumar, Ashok

2015-01-01

Food-borne illnesses pose a real scourge in the present scenario as the consumerism of packaged food has increased to a great extend. Pathogens entering the packaged foods may survive longer, which needs a check. Antimicrobial agents either alone or in combination are added to the food or packaging materials for this purpose. Exploiting the antimicrobial property, essential oils are considered as a "natural" remedy to this problem other than its flavoring property instead of using synthetic agents. The essential oils are well known for its antibacterial, antiviral, antimycotic, antiparasitic, and antioxidant properties due to the presence of phenolic functional group. Gram-positive organisms are found more susceptible to the action of the essential oils. Essential oils improve the shelf-life of packaged products, control the microbial growth, and unriddle the consumer concerns regarding the use of chemical preservatives. This review is intended to provide an overview of the essential oils and their role as natural antimicrobial agents in the food industry.

Consumers' ratings of the natural and unnatural qualities of foods.

PubMed

Evans, Greg; de Challemaison, Blandine; Cox, David N

2010-06-01

An investigation sought to understand what consumers perceive by the term natural. The aim was to test eight hypotheses on food ingredients and processes used for manufactured food. A representative sample (n=190, aged 18-65 years), rated 50 food exemplars for naturalness (0-100 scale). Data were analysed by repeated measures ANOVA. Results support three hypotheses: chemical changes were more potent than physical changes; there was a minimal effect of mixing like entities and the more processing the greater the effect on consumer's deviation away from natural. Two hypotheses were validated conditionally: contagion accounts for naturalness reduction but is independent of dose above a certain level; E-numbers were always perceived to be less natural than the same preservatives described by chemical and common names; however, there were gender and some education interaction effects. The hypothesis that addition has a greater effect than removal was only partially validated. There was no evidence found to support the hypotheses that process has more effect than content, or that novel ingredients have a greater effect than 'known' ingredients, however, this result may have been confounded. The implications for new manufactured food products, suggested by the results, are that products with physical changes, less processing, with like ingredients and described using common named descriptors for ingredients would be perceived to be more natural. Copyright 2010 Elsevier Ltd. All rights reserved.

Importance of perceived naturalness for acceptance of food additives and cultured meat.

PubMed

Siegrist, Michael; Sütterlin, Bernadette

2017-06-01

Four experiments examined some factors influencing the perceived naturalness of food products and their biasing effect on risk perception. The results of Experiment 1a showed that three food additives displaying their respective E-numbers (i.e., codes for food additives in the European Union and Switzerland) decreased perceived naturalness. Experiment 1b demonstrated that mentioning possible health effects decreased the perceived naturalness of a plant-based food additive. This experiment further showed that it would not matter for perceived naturalness whether the food was synthetic or nature-identical. Moreover, the results of Experiments 2 and 3 suggested that the same risk associated with meat consumption was much more acceptable for traditionally produced meat compared with in-vitro meat. Experiment 3 further indicated that the perceived naturalness of the meat (i.e., traditional or cultured meat) had a full mediation effect on participants' evaluation of the acceptability of the risk of colon cancer associated with the meat consumption. Even if the new production method (i.e., cultured meat) was more environmentally friendly and less harmful to animals, the perceived lack of naturalness might reduce the acceptability of the risk associated with such a product. The present study provides evidence that consumers rely on symbolic information when evaluating foods, which may lead to biased judgments and decisions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Aromatic Polyketide GTRI-02 is a Previously Unidentified Product of the act Gene Cluster in Streptomyces coelicolor A3(2).

PubMed

Wu, Changsheng; Ichinose, Koji; Choi, Young Hae; van Wezel, Gilles P

2017-07-18

The biosynthesis of aromatic polyketides derived from type II polyketide synthases (PKSs) is complex, and it is not uncommon that highly similar gene clusters give rise to diverse structural architectures. The act biosynthetic gene cluster (BGC) of the model actinomycete Streptomyces coelicolor A3(2) is an archetypal type II PKS. Here we show that the act BGC also specifies the aromatic polyketide GTRI-02 (1) and propose a mechanism for the biogenesis of its 3,4-dihydronaphthalen-1(2H)-one backbone. Polyketide 1 was also produced by Streptomyces sp. MBT76 after activation of the act-like qin gene cluster by overexpression of the pathway-specific activator. Mining of this strain also identified dehydroxy-GTRI-02 (2), which most likely originated from dehydration of 1 during the isolation process. This work shows that even extensively studied model gene clusters such as act of S. coelicolor can still produce new chemistry, offering new perspectives for drug discovery. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Identification and characterization of the polyketide synthase involved in ochratoxin A biosynthesis in Aspergillus carbonarius

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallo, Antonia; Knox, Benjamin P.; Bruno, Kenneth S.

2014-06-02

Ochratoxin A (OTA) is a potent mycotoxin produced by Aspergillus and Penicillium species and is a common contaminant of a wide variety of food commodities, with Aspergillus carbonarius being the main producer of OTA contamination in grapes and wine. The molecular structure of OTA is composed of a dihydroisocoumarin ring linked to phenylalanine and, as shown in different producing fungal species, a polyketide synthase (PKS) is a component of the OTA biosynthetic pathway. Similar to observations in other filamentous ascomycetes, the genome sequence of A. carbonarius contains a large number of genes predicted to encode PKSs. In this work amore » pks gene identified within the putative OTA cluster of A. carbonarius, designated as AcOTApks, was inactivated and the resulting mutant strain was unable to produce OTA, confirming the role of AcOTApks in this biosynthetic pathway. AcOTApks protein is characteristic of the highly reduced (HR)-PKS family, and also contains a putative methyltransferase domain likely responsible for the addition of the methyl group to the OTA polyketide structure. AcOTApks is different from the ACpks protein that we previously described which showed an expression profile compatible with OTA production. We performed phylogenetic analyses of the β-ketosynthase and acyl-transferase domains of the OTA PKSs which had been identified and characterized in different OTA producing fungal species. The phylogenetic results were similar for both the two domains analyzed and showed that OTA PKS of A. carbonarius, Aspergillus niger, and Aspergillus ochraceus clustered in a monophyletic group with 100% bootstrap support suggesting a common origin, while the other OTA PKSs analyzed were phylogenetically distant. A qRT-PCR assay monitored AcOTApks expression during fungal growth and concomitant production of OTA by A. carbonarius in synthetic grape medium. A clear correlation between the expression profile of AcOTApks and kinetics of OTA production was

The Polyketide Components of Waxes and the Cer-cqu Gene Cluster Encoding a Novel Polyketide Synthase, the β-Diketone Synthase, DKS

PubMed Central

von Wettstein-Knowles, Penny

2017-01-01

The primary function of the outermost, lipophilic layer of plant aerial surfaces, called the cuticle, is preventing non-stomatal water loss. Its exterior surface is often decorated with wax crystals, imparting a blue–grey color. Identification of the barley Cer-c, -q and -u genes forming the 101 kb Cer-cqu gene cluster encoding a novel polyketide synthase—the β-diketone synthase (DKS), a lipase/carboxyl transferase, and a P450 hydroxylase, respectively, establishes a new, major pathway for the synthesis of plant waxes. The major product is a β-diketone (14,16-hentriacontane) aliphatic that forms long, thin crystalline tubes. A pathway branch leads to the formation of esterified alkan-2-ols. PMID:28698520

The Polyketide Components of Waxes and the Cer-cqu Gene Cluster Encoding a Novel Polyketide Synthase, the β-Diketone Synthase, DKS.

PubMed

von Wettstein-Knowles, Penny

2017-07-10

The primary function of the outermost, lipophilic layer of plant aerial surfaces, called the cuticle, is preventing non-stomatal water loss. Its exterior surface is often decorated with wax crystals, imparting a blue-grey color. Identification of the barley Cer-c , -q and -u genes forming the 101 kb Cer-cqu gene cluster encoding a novel polyketide synthase-the β-diketone synthase (DKS), a lipase/carboxyl transferase, and a P450 hydroxylase, respectively, establishes a new, major pathway for the synthesis of plant waxes. The major product is a β-diketone (14,16-hentriacontane) aliphatic that forms long, thin crystalline tubes. A pathway branch leads to the formation of esterified alkan-2-ols.

Genomes to natural products PRediction Informatics for Secondary Metabolomes (PRISM).

PubMed

Skinnider, Michael A; Dejong, Chris A; Rees, Philip N; Johnston, Chad W; Li, Haoxin; Webster, Andrew L H; Wyatt, Morgan A; Magarvey, Nathan A

2015-11-16

Microbial natural products are an invaluable source of evolved bioactive small molecules and pharmaceutical agents. Next-generation and metagenomic sequencing indicates untapped genomic potential, yet high rediscovery rates of known metabolites increasingly frustrate conventional natural product screening programs. New methods to connect biosynthetic gene clusters to novel chemical scaffolds are therefore critical to enable the targeted discovery of genetically encoded natural products. Here, we present PRISM, a computational resource for the identification of biosynthetic gene clusters, prediction of genetically encoded nonribosomal peptides and type I and II polyketides, and bio- and cheminformatic dereplication of known natural products. PRISM implements novel algorithms which render it uniquely capable of predicting type II polyketides, deoxygenated sugars, and starter units, making it a comprehensive genome-guided chemical structure prediction engine. A library of 57 tailoring reactions is leveraged for combinatorial scaffold library generation when multiple potential substrates are consistent with biosynthetic logic. We compare the accuracy of PRISM to existing genomic analysis platforms. PRISM is an open-source, user-friendly web application available at http://magarveylab.ca/prism/. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Molecular variation of the nonribosomal peptide-polyketide siderophore yersiniabactin through biosynthetic and metabolic engineering.

PubMed

Ahmadi, Mahmoud Kamal; Fawaz, Samar; Fang, Lei; Yu, Zhipeng; Pfeifer, Blaine A

2016-05-01

The production of the mixed nonribosomal peptide-polyketide natural product yersiniabactin (Ybt) has been established using E. coli as a heterologous host. In this study, precursor-directed biosynthesis was used to generate five new analogs of Ybt, demonstrating the flexibility of the heterologous system and the biosynthetic process in allowing compound diversity. A combination of biosynthetic and cellular engineering was then used to influence the production metrics of the resulting analogs. First, the cellular levels and activity of FadL, a hydrocarbon transport protein, were tested for subsequent influence upon exogenous precursor uptake and Ybt analog production with a positive correlation observed between FadL over-production and analog formation. Next, a Ybt biosynthetic editing enzyme was removed from the heterologous system which decreased native compound production but increased analog formation. A final series of experiments enhanced endogenous anthranilate towards complete pathway formation of the associated analog which showed a selective ability to bind gold. © 2015 Wiley Periodicals, Inc.

Exploring the relationship between nature sounds, connectedness to nature, mood and willingness to buy sustainable food: A retail field experiment.

PubMed

Spendrup, Sara; Hunter, Erik; Isgren, Ellinor

2016-05-01

Nature sounds are increasingly used by some food retailers to enhance in-store ambiance and potentially even influence sustainable food choices. An in-store, 2 × 3 between-subject full factorial experiment conducted on 627 customers over 12 days tested whether nature sound directly and indirectly influenced willingness to buy (WTB) sustainable foods. The results show that nature sounds positively and directly influence WTB organic foods in groups of customers (men) that have relatively low initial intentions to buy. Indirectly, we did not find support for the effect of nature sound on influencing mood or connectedness to nature (CtN). However, we show that information on the product's sustainability characteristics moderates the relationship between CtN and WTB in certain groups. Namely, when CtN is high, sustainability information positively moderated WTB both organic and climate friendly foods in men. Conversely, when CtN was low, men expressed lower WTB organic and climate friendly foods than identical, albeit conventionally labelled products. Consequently, our study concludes that nature sounds might be an effective, yet subtle in-store tool to use on groups of consumers who might otherwise respond negatively to more overt forms of sustainable food information. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modified lysozymes as novel broad spectrum natural antimicrobial agents in foods.

PubMed

Aminlari, Ladan; Hashemi, Marjan Mohammadi; Aminlari, Mahmoud

2014-06-01

In recent years much attention and interest have been directed toward application of natural antimicrobial agents in foods. Some naturally occurring proteins such as lactoperoxidase, lactoferrin, and lysozyme have received considerable attention and are being considered as potential antimicrobial agents in foods. Lysozyme kills bacteria by hydrolyzing the peptidoglycan layer of the cell wall of certain bacterial species, hence its application as a natural antimicrobial agent has been suggested. However, limitations in the action of lysozyme against only Gram-positive bacteria have prompted scientists to extend the antimicrobial effects of lysozyme by several types of chemical modifications. During the last 2 decades extensive research has been directed toward modification of lysozyme in order to improve its antimicrobial properties. This review will report on the latest information available on lysozyme modifications and examine the applicability of the modified lysozymes in controlling growth of Gram-positive and Gram-negative bacteria in foods. The results of modifications of lysozyme using its conjugation with different small molecule, polysaccharides, as well as modifications using proteolytic enzymes will be reviewed. These types of modifications have not only increased the functional properties of lysozyme (such as solubility and heat stability) but also extended the antimicrobial activity of lysozyme. Many examples will be given to show that modification can decrease the count of Gram-negative bacteria in bacterial culture and in foods by as much as 5 log CFU/mL and in some cases essentially eliminated Escherichia coli. In conclusion this review demonstrates that modified lysozymes are excellent natural food preservatives, which can be used in food industry. The subject described in this review article can lead to the development of methods to produce new broad-spectrum natural antimicrobial agents, based on modification of chicken egg white lysozyme, which

Simultaneous identification of synthetic and natural dyes in different food samples by UPLC-MS

NASA Astrophysics Data System (ADS)

Mandal, Badal Kumar; Mathiyalagan, Siva; Dalavai, Ramesh; Ling, Yong-Chien

2017-11-01

Fast foods and variety food items are populating among the food lovers. To improve the appearance of the food product in surviving gigantic competitive environment synthetic or natural food dyes are added to food items and beverages. Although regulatory bodies permit addition of natural colorants due to its safe and nontoxic nature in food, synthetic dyes are stringently controlled in all food products due to their toxicity by regulatory bodies. Artificial colors are need certification from the regulatory bodies for human consumption. To analyze food dyes in different food samples many analytical techniques are available like high pressure liquid chromatography (HPLC), thin layer chromatography (TLC), spectroscopic and gas chromatographic methods. However all these reported methods analyzed only synthetic dyes or natural dyes. Not a single method has analyzed both synthetic and natural dyes in a single run. In this study a robust ultra-performance liquid chromatographic method for simultaneous identification of 6 synthetic dyes (Tartrazine, Indigo carmine, Briliant blue, Fast green, malachite green, sunset yellow) and one natural dye (Na-Cu-Chlorophyllin) was developed using acquitic UPLC system equipped with Mass detector and acquity UPLC HSS T3 column (1.8 μm, 2.1 × 50 mm, 100Å). All the dyes were separated and their masses were determined through fragments’ masses analyses.

The enzymology of polyether biosynthesis.

PubMed

Liu, Tiangang; Cane, David E; Deng, Zixin

2009-01-01

Polyether ionophore antibiotics are a special class of polyketides widely used in veterinary medicine, and as food additives in animal husbandry. In this article, we review current knowledge about the mechanism of polyether biosynthesis, and the genetic and biochemical strategies used for its study. Several clear differences distinguish it from traditional type I modular polyketide biosynthesis: polyether backbones are assembled by modular polyketide synthases but are modified by two key enzymes, epoxidase and epoxide hydrolase, to generate the product. All double bonds involved in the oxidative cyclization in the polyketide backbone are of E geometry. Chain release in the polyether biosynthetic pathway requires a special type II thioesterase which specifically hydrolyzes the polyether thioester. All these discoveries should be very helpful for a deep understanding of the biosynthetic mechanism of this class of important natural compounds, and for the targeted engineering of polyether derivatives.

Food and Natural Materials Target Mechanisms to Effectively Regulate Allergic Responses.

PubMed

Shin, Hee Soon; Shon, Dong-Hwa

2015-01-01

An immune hypersensitivity disorder called allergy is caused by diverse allergens entering the body via skin contact, injection, ingestion, and/or inhalation. These allergic responses may develop into allergic disorders, including inflammations such as atopic dermatitis, asthma, anaphylaxis, food allergies, and allergic rhinitis. Several drugs have been developed to treat these allergic disorders; however, long-term intake of these drugs could have adverse effects. As an alternative to these medicines, food and natural materials that ameliorate allergic disorder symptoms without producing any side effects can be consumed. Food and natural materials can effectively regulate successive allergic responses in an allergic chain-reaction mechanism in the following ways: [1] Inhibition of allergen permeation via paracellular diffusion into epithelial cells, [2] suppression of type 2 T-helper (Th) cell-related cytokine production by regulating Th1/Th2 balance, [3] inhibition of pathogenic effector CD4(+) T cell differentiation by inducing regulatory T cells (Treg), and [4] inhibition of degranulation in mast cells. The immunomodulatory effects of food and natural materials on each target mechanism were scientifically verified and shown to alleviate allergic disorder symptoms. Furthermore, consumption of certain food and natural materials such as fenugreek, skullcap, chitin/chitosan, and cheonggukjang as anti-allergics have merits such as safety (no adverse side effects), multiple suppressive effects (as a mixture would contain various components that are active against allergic responses), and ease of consumption when required. These merits and anti-allergic properties of food and natural materials help control various allergic disorders.

The safety and regulation of natural products used as foods and food ingredients.

PubMed

Abdel-Rahman, Ali; Anyangwe, Njwen; Carlacci, Louis; Casper, Steve; Danam, Rebecca P; Enongene, Evaristus; Erives, Gladys; Fabricant, Daniel; Gudi, Ramadevi; Hilmas, Corey J; Hines, Fred; Howard, Paul; Levy, Dan; Lin, Ying; Moore, Robert J; Pfeiler, Erika; Thurmond, T Scott; Turujman, Saleh; Walker, Nigel J

2011-10-01

The use of botanicals and dietary supplements derived from natural substances as an adjunct to an improved quality of life or for their purported medical benefits has become increasingly common in the United States. This review addresses the safety assessment and regulation of food products containing these substances by the U.S. Food and Drug Administration (FDA). The issue of safety is particularly critical given how little information is available on the toxicity of some of these products. The first section uses case studies for stevia and green tea extracts as examples of how FDA evaluates the safety of botanical and herbal products submitted for consideration as Generally Recognized as Safe under the Federal Food, Drug, and Cosmetics Act. The 1994 Dietary Supplement Health Education Act (DSHEA) created a regulatory framework for dietary supplements. The article also discusses the regulation of this class of dietary supplements under DSHEA and addresses the FDA experience in analyzing the safety of natural ingredients described in pre-market safety submissions. Lastly, we discuss an ongoing interagency collaboration to conduct safety testing of nominated dietary supplements.

Polyketides with Immunosuppressive Activities from Mangrove Endophytic Fungus Penicillium sp. ZJ-SY₂.

PubMed

Liu, Hongju; Chen, Senhua; Liu, Weiyang; Liu, Yayue; Huang, Xishan; She, Zhigang

2016-11-25

Nine polyketides, including two new benzophenone derivatives, peniphenone ( 1 ) and methyl peniphenone ( 2 ), along with seven known xanthones ( 3 - 9 ) were obtained from mangrove endophytic fungus Penicillium sp. ZJ-SY₂ isolated from the leaves of Sonneratia apetala . Their structures were elucidated on the basis of MS, 1D, and 2D NMR data. Compounds 1 , 3 , 5 , and 7 showed potent immunosuppressive activity with IC 50 values ranging from 5.9 to 9.3 μg/mL.

Natural history of perceived food hypersensitivity and IgE sensitisation to food allergens in a cohort of adults.

PubMed

Patelis, Antonios; Gunnbjörnsdottir, Maria; Borres, Magnus P; Burney, Peter; Gislason, Thorarinn; Torén, Kjell; Forsberg, Bertil; Alving, Kjell; Malinovschi, Andrei; Janson, Christer

2014-01-01

No longitudinal studies exist on the natural history of food hypersensitivity and IgE sensitisation to food allergens in adults. To examine the natural history of food hypersensitivity, the natural history of IgE sensitisation to food allergens and to investigate the risk factors for new onset food hypersensitivity. Food hypersensitivity was questionnaire-assessed in 2307 individuals (aged 20-45 years) from Iceland and Sweden during the European Community Respiratory Health Survey both at baseline and follow-up 9 years later. IgE food and aeroallergen sensitisation were assessed in a subgroup of these individuals (n = 807). Values of 0.35 kU/L and above were regarded as positive sensitisation. Food hypersensitivity was reported by 21% of the subjects and this proportion remained unchanged at follow-up (p = 0.58). Fruits, nuts and vegetables were the three most common causes of food hypersensitivity, with a similar prevalence at baseline and follow-up. The prevalence IgE sensitisation to food allergens decreased in general by 56% (p<0.001) and IgE sensitisation to peanut decreased in particular by 67% (p = 0.003). The prevalence of timothy grass IgE sensitisation decreased by 15% (p = 0.003) while cat, mite and birch IgE sensitisation did not decrease significantly. Female sex, rhinitis, eczema and presence of IgE sensitisation to aeroallergens were independently associated with new onset food hypersensitivity. The prevalence of food hypersensitivity remained unchanged while the prevalence of IgE sensitisation to food allergens decreased in adults over a 9-year follow-up period. The decrease in prevalence of IgE sensitisation to food allergens was considerably larger than the change in prevalence of IgE sensitisation to aeroallergens.

Natural History of Perceived Food Hypersensitivity and IgE Sensitisation to Food Allergens in a Cohort of Adults

PubMed Central

Patelis, Antonios; Gunnbjörnsdottir, Maria; Borres, Magnus P.; Burney, Peter; Gislason, Thorarinn; Torén, Kjell; Forsberg, Bertil; Alving, Kjell

2014-01-01

Background No longitudinal studies exist on the natural history of food hypersensitivity and IgE sensitisation to food allergens in adults. Objective To examine the natural history of food hypersensitivity, the natural history of IgE sensitisation to food allergens and to investigate the risk factors for new onset food hypersensitivity. Methods Food hypersensitivity was questionnaire-assessed in 2307 individuals (aged 20–45 years) from Iceland and Sweden during the European Community Respiratory Health Survey both at baseline and follow-up 9 years later. IgE food and aeroallergen sensitisation were assessed in a subgroup of these individuals (n = 807). Values of 0.35 kU/L and above were regarded as positive sensitisation. Results Food hypersensitivity was reported by 21% of the subjects and this proportion remained unchanged at follow-up (p = 0.58). Fruits, nuts and vegetables were the three most common causes of food hypersensitivity, with a similar prevalence at baseline and follow-up. The prevalence IgE sensitisation to food allergens decreased in general by 56% (p<0.001) and IgE sensitisation to peanut decreased in particular by 67% (p = 0.003). The prevalence of timothy grass IgE sensitisation decreased by 15% (p = 0.003) while cat, mite and birch IgE sensitisation did not decrease significantly. Female sex, rhinitis, eczema and presence of IgE sensitisation to aeroallergens were independently associated with new onset food hypersensitivity. Conclusion The prevalence of food hypersensitivity remained unchanged while the prevalence of IgE sensitisation to food allergens decreased in adults over a 9-year follow-up period. The decrease in prevalence of IgE sensitisation to food allergens was considerably larger than the change in prevalence of IgE sensitisation to aeroallergens. PMID:24427301

Putative Monofunctional Type I Polyketide Synthase Units: A Dinoflagellate-Specific Feature?

PubMed Central

Eichholz, Karsten; Beszteri, Bánk; John, Uwe

2012-01-01

Marine dinoflagellates (alveolata) are microalgae of which some cause harmful algal blooms and produce a broad variety of most likely polyketide synthesis derived phycotoxins. Recently, novel polyketide synthesase (PKS) transcripts have been described from the Florida red tide dinoflagellate Karenia brevis (gymnodiniales) which are evolutionarily related to Type I PKS but were apparently expressed as monofunctional proteins, a feature typical of Type II PKS. Here, we investigated expression units of PKS I-like sequences in Alexandrium ostenfeldii (gonyaulacales) and Heterocapsa triquetra (peridiniales) at the transcript and protein level. The five full length transcripts we obtained were all characterized by polyadenylation, a 3′ UTR and the dinoflagellate specific spliced leader sequence at the 5′end. Each of the five transcripts encoded a single ketoacylsynthase (KS) domain showing high similarity to K. brevis KS sequences. The monofunctional structure was also confirmed using dinoflagellate specific KS antibodies in Western Blots. In a maximum likelihood phylogenetic analysis of KS domains from diverse PKSs, dinoflagellate KSs formed a clade placed well within the protist Type I PKS clade between apicomplexa, haptophytes and chlorophytes. These findings indicate that the atypical PKS I structure, i.e., expression as putative monofunctional units, might be a dinoflagellate specific feature. In addition, the sequenced transcripts harbored a previously unknown, apparently dinoflagellate specific conserved N-terminal domain. We discuss the implications of this novel region with regard to the putative monofunctional organization of Type I PKS in dinoflagellates. PMID:23139807

The water-food nexus of natural rubber production

NASA Astrophysics Data System (ADS)

Chiarelli, D. D.; Rosa, L.; Rulli, M. C.; D'Odorico, P.

2017-12-01

The increasing global demand for natural rubber (100% increase in the last 15 years) is for most part met by Malaysia and Indonesia, and - to a lesser extent - other countries in south-east Asia and Africa. The consequent expansion of rubber plantation has often occurred at the expenses of agricultural land for staple food, particularly in southeast Asia, where most of the land suitable for agriculture is already harvested for food crops or other uses. Here we investigate the extent to which the ongoing increase in rubber production is competing with the food system and affecting the livelihoods of rural communities in the areas of production and their appropriation of natural resources, such as water. We also investigate to what extent the expansion of rubber plantations is taking place through large scale land acquisitions (LSLAs) and evaluate the impacts on rural communities. Our results show how rubber production has strong environmental, social and economic impacts. Despite their ability to bring employment and increase the average income of economically disadvantaged areas, rubber plantations may threaten the local water and food security and induce a loss of rural livelihoods, particularly when the new plantations result from LSLAs that displace semi-subsistence forms of production thereby forcing the local populations to depend on global markets.

Polyketide biosynthesis in dinoflagellates: what makes it different?

PubMed

Van Wagoner, Ryan M; Satake, Masayuki; Wright, Jeffrey L C

2014-09-01

Dinoflagellates produce unique polyketides characterized by their size and complexity. The biosynthesis of a limited number of such metabolites has been reported, with studies largely hampered by the low yield of compounds and the severe scrambling of label in the isotopically-labeled precursors. Nonetheless, of the successful biosynthetic experiments that have been reported, many surprising and unique processes have been discovered. This knowledge has been accessed through a series of biochemical labeling studies, and while limited molecular genetic data has been amassed, it is still in the early stages of development. In an attempt to meet this challenge, this review has compared some of the biosynthetic processes with similar ones identified in other microbes such as bacteria and myxobacteria, with the idea that similar genes and enzymes are employed by dinoflagellates.

Status, Antimicrobial Mechanism, and Regulation of Natural Preservatives in Livestock Food Systems.

PubMed

Lee, Na-Kyoung; Paik, Hyun-Dong

2016-01-01

This review discusses the status, antimicrobial mechanisms, application, and regulation of natural preservatives in livestock food systems. Conventional preservatives are synthetic chemical substances including nitrates/nitrites, sulfites, sodium benzoate, propyl gallate, and potassium sorbate. The use of artificial preservatives is being reconsidered because of concerns relating to headache, allergies, and cancer. As the demand for biopreservation in food systems has increased, new natural antimicrobial compounds of various origins are being developed, including plant-derived products (polyphenolics, essential oils, plant antimicrobial peptides (pAMPs)), animal-derived products (lysozymes, lactoperoxidase, lactoferrin, ovotransferrin, antimicrobial peptide (AMP), chitosan and others), and microbial metabolites (nisin, natamycin, pullulan, ε-polylysine, organic acid, and others). These natural preservatives act by inhibiting microbial cell walls/membranes, DNA/RNA replication and transcription, protein synthesis, and metabolism. Natural preservatives have been recognized for their safety; however, these substances can influence color, smell, and toxicity in large amounts while being effective as a food preservative. Therefore, to evaluate the safety and toxicity of natural preservatives, various trials including combinations of other substances or different food preservation systems, and capsulation have been performed. Natamycin and nisin are currently the only natural preservatives being regulated, and other natural preservatives will have to be legally regulated before their widespread use.

Status, Antimicrobial Mechanism, and Regulation of Natural Preservatives in Livestock Food Systems

PubMed Central

Lee, Na-Kyoung; Paik, Hyun-Dong

2016-01-01

This review discusses the status, antimicrobial mechanisms, application, and regulation of natural preservatives in livestock food systems. Conventional preservatives are synthetic chemical substances including nitrates/nitrites, sulfites, sodium benzoate, propyl gallate, and potassium sorbate. The use of artificial preservatives is being reconsidered because of concerns relating to headache, allergies, and cancer. As the demand for biopreservation in food systems has increased, new natural antimicrobial compounds of various origins are being developed, including plant-derived products (polyphenolics, essential oils, plant antimicrobial peptides (pAMPs)), animal-derived products (lysozymes, lactoperoxidase, lactoferrin, ovotransferrin, antimicrobial peptide (AMP), chitosan and others), and microbial metabolites (nisin, natamycin, pullulan, ε-polylysine, organic acid, and others). These natural preservatives act by inhibiting microbial cell walls/membranes, DNA/RNA replication and transcription, protein synthesis, and metabolism. Natural preservatives have been recognized for their safety; however, these substances can influence color, smell, and toxicity in large amounts while being effective as a food preservative. Therefore, to evaluate the safety and toxicity of natural preservatives, various trials including combinations of other substances or different food preservation systems, and capsulation have been performed. Natamycin and nisin are currently the only natural preservatives being regulated, and other natural preservatives will have to be legally regulated before their widespread use. PMID:27621697

Curvularides A-E: antifungal hybrid peptide-polyketides from the endophytic fungus Curvularia geniculata.

PubMed

Chomcheon, Porntep; Wiyakrutta, Suthep; Aree, Thammarat; Sriubolmas, Nongluksna; Ngamrojanavanich, Nattaya; Mahidol, Chulabhorn; Ruchirawat, Somsak; Kittakoop, Prasat

2010-09-24

Five new hybrid peptide-polyketides, curvularides A-E (1-5), were isolated from the endophytic fungus Curvularia geniculata, which was obtained from the limbs of Catunaregam tomentosa. Structure elucidation for curvularides A-E (1-5) was accomplished by analysis of spectroscopic data, as well as by single-crystal X-ray crystallography. Curvularide B (2) exhibited antifungal activity against Candida albicans, and it also showed synergistic activity with a fluconazole drug.

Natural or Organic Foods? [Project ECOLogy ELE Pak, Schmidt Pak].

ERIC Educational Resources Information Center

Schmidt, Linda

This is one of a series of units for environmental education developed by the Highline Public Schools. The unit is designed for secondary students in home economics classes. The content of the units focuses on natural and organic foods, characteristics of the foods, and uses of the foods. The seven lessons in this unit are designed to last over a…

Nutritional Noise: Community Literacies and the Movement against Foods Labeled as "Natural"

ERIC Educational Resources Information Center

Trauth, Erin

2015-01-01

In the face of the $44 billion market--and rising--for foods labeled as "natural" (despite any formal regulatory oversight on the use of this term), this article examines multiple complex layers of community literacies and movements involving foods labeled as "natural," including an increasing availability of…

Chaetochromones A and B, two new polyketides from the fungus Chaetomium indicum (CBS.860.68).

PubMed

Lu, Keyang; Zhang, Yisheng; Li, Li; Wang, Xuewei; Ding, Gang

2013-09-05

Chaetochromones A (1) and B (2), two novel polyketides, were isolated from the crude extract of fungus Chaetomium indicum (CBS.860.68) together with three known analogues PI-3(3), PI-4 (4) and SB236050 (5). The structures of these compounds were determined by HRESI-MS and NMR experiments. Chaetochromones A (1) and B (2) are a member of the polyketides family, which might originate from a similar biogenetic pathway as the known compounds PI-3 (3), PI-4 (4) and SB236050 (5). The biological activities of these secondary metabolites were evaluated against eight plant pathogens, including Alternaria alternata, Ilyonectria radicicola, Trichoderma viride pers, Aspergillus niger, Fusarium verticillioide, Irpex lacteus (Fr.), Poria placenta (Fr.) Cooke and Coriolus versicolor (L.) Quél. Compound 1 displayed moderate inhibitory rate (>60%) against the brown rot fungus Poria placenta (Fr.) Cooke, which causes significant wood decay. In addition, the cytotoxic activities against three cancer cell lines A549, MDA-MB-231, PANC-1 were also tested, without any inhibitory activities being detected.

Pestalpolyols A-D, Cytotoxic Polyketides from Pestalotiopsis sp. cr013.

PubMed

Li, Jing; Xie, Jin; Yang, Yin-He; Li, Xiao-Lian; Zeng, Ying; Zhao, Pei-Ji

2015-09-01

Four novel polyketides, named pestalpolyols A (1), B (2), C (3), and D (4), were isolated from solid fermentation products of Pestalotiopsis sp. cr013. Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D nuclear magnetic resonance and high-resolution electrospray ionization mass spectrometry experiments, and the absolute configuration was confirmed by single-crystal X-ray diffraction analysis using the anomalous scattering of Cu Kα radiation. The inhibitory activities of compounds 1, 2, and 4 against five human tumor lines were tested in vitro, and showed IC50 values 2.3-31.2 µM. Georg Thieme Verlag KG Stuttgart · New York.

Engineering cofactor and transport mechanisms in Saccharomyces cerevisiae for enhanced acetyl-CoA and polyketide biosynthesis.

PubMed

Cardenas, Javier; Da Silva, Nancy A

2016-07-01

Synthesis of polyketides at high titer and yield is important for producing pharmaceuticals and biorenewable chemical precursors. In this work, we engineered cofactor and transport pathways in Saccharomyces cerevisiae to increase acetyl-CoA, an important polyketide building block. The highly regulated yeast pyruvate dehydrogenase bypass pathway was supplemented by overexpressing a modified Escherichia coli pyruvate dehydrogenase complex (PDHm) that accepts NADP(+) for acetyl-CoA production. After 24h of cultivation, a 3.7-fold increase in NADPH/NADP(+) ratio was observed relative to the base strain, and a 2.2-fold increase relative to introduction of the native E. coli PDH. Both E. coli pathways increased acetyl-CoA levels approximately 2-fold relative to the yeast base strain. Combining PDHm with a ZWF1 deletion to block the major yeast NADPH biosynthesis pathway resulted in a 12-fold NADPH boost and a 2.2-fold increase in acetyl-CoA. At 48h, only this coupled approach showed increased acetyl-CoA levels, 3.0-fold higher than that of the base strain. The impact on polyketide synthesis was evaluated in a S. cerevisiae strain expressing the Gerbera hybrida 2-pyrone synthase (2-PS) for the production of the polyketide triacetic acid lactone (TAL). Titers of TAL relative to the base strain improved only 30% with the native E. coli PDH, but 3.0-fold with PDHm and 4.4-fold with PDHm in the Δzwf1 strain. Carbon was further routed toward TAL production by reducing mitochondrial transport of pyruvate and acetyl-CoA; deletions in genes POR2, MPC2, PDA1, or YAT2 each increased titer 2-3-fold over the base strain (up to 0.8g/L), and in combination to 1.4g/L. Combining the two approaches (NADPH-generating acetyl-CoA pathway plus reduced metabolite flux into the mitochondria) resulted in a final TAL titer of 1.6g/L, a 6.4-fold increase over the non-engineered yeast strain, and 35% of theoretical yield (0.16g/g glucose), the highest reported to date. These biological driving

Policing starter unit selection of the enterocin type II polyketide synthase by the type II thioesterase EncL.

PubMed

Kalaitzis, John A; Cheng, Qian; Meluzzi, Dario; Xiang, Longkuan; Izumikawa, Miho; Dorrestein, Pieter C; Moore, Bradley S

2011-11-15

Enterocin is an atypical type II polyketide synthase (PKS) product from the marine actinomycete 'Streptomyces maritimus'. The enterocin biosynthesis gene cluster (enc) codes for proteins involved in the assembly and attachment of the rare benzoate primer that initiates polyketide assembly with the addition of seven malonate molecules and culminates in a Favorskii-like rearrangement of the linear poly-β-ketone to give its distinctive non-aromatic, caged core structure. Fundamental to enterocin biosynthesis, which utilizes a single acyl carrier protein (ACP), EncC, for both priming with benzoate and elongating with malonate, involves maintaining the correct balance of acyl-EncC substrates for efficient polyketide assembly. Here, we report the characterization of EncL as a type II thioesterase that functions to edit starter unit (mis)priming of EncC. We performed a series of in vivo mutational studies, heterologous expression experiments, in vitro reconstitution studies, and Fourier-transform mass spectrometry-monitored competitive enzyme assays that together support the proposed selective hydrolase activity of EncL toward misprimed acetyl-ACP over benzoyl-ACP to facilitate benzoyl priming of the enterocin PKS complex. While this system resembles the R1128 PKS that also utilizes an editing thioesterase (ZhuC) to purge acetate molecules from its initiation module ACP in favor of alkylacyl groups, the enterocin system is distinct in its usage of a single ACP for both priming and elongating reactions with different substrates. Copyright © 2011 Elsevier Ltd. All rights reserved.

Policing Starter Unit Selection of the Enterocin Type II Polyketide Synthase by the Type II Thioesterase EncL

PubMed Central

Kalaitzis, John A.; Cheng, Qian; Meluzzi, Dario; Xiang, Longkuan; Izumikawa, Miho; Dorrestein, Pieter C.; Moore, Bradley S.

2011-01-01

Enterocin is an atypical type II polyketide synthase (PKS) product from the marine actinomycete “Streptomyces maritimus”. The enterocin biosynthesis gene cluster (enc) codes for proteins involved in the assembly and attachment of the rare benzoate primer that initiates polyketide assembly with the addition of seven malonate molecules and culminates in a Favorskii-like rearrangement of the linear poly-β-ketone to give its distinctive non-aromatic, caged core structure. Fundamental to enterocin biosynthesis, which utilizes a single acyl carrier protein (ACP), EncC, for both priming with benzoate and elongating with malonate, involves maintaining the correct balance of acyl-EncC substrates for efficient polyketide assembly. Here we report the characterization of EncL as a type II thioesterase that functions to edit starter unit (mis)priming of EncC. We performed a series of in vivo mutational studies, heterologous expression experiments, in vitro reconstitution studies, and Fourier-transform mass spectrometry-monitored competitive enzyme assays that together support the proposed selective hydrolase activity of EncL toward misprimed acetyl-ACP over benzoyl-ACP to facilitate benzoyl priming of the enterocin PKS complex. While this system resembles the R1128 PKS that also utilizes an editing thioesterase (ZhuC) to purge acetate molecules from its initiation module ACP in favor of alkylacyl groups, the enterocin system is distinct in its usage of a single ACP for both priming and elongating reactions with different substrates. PMID:21531566

The marine sponge-derived polyketide endoperoxide plakortide F acid mediates its antifungal activity by interfering with calcium homeostasis

USDA-ARS?s Scientific Manuscript database

Plakortide F acid (PFA) is a marine-derived polyketide endoperoxide exhibiting strong inhibitory activity against several clinically important fungal pathogens. In the present study, transcriptional profiling coupled with mutant and biochemical analyses were conducted using the model organism Sacch...

The “Natural” vs. “Natural Flavors” Conflict in Food Labeling: A Regulatory Viewpoint.

PubMed

Goodman, Matthew J

Food branded with a Natural label can be found in any grocery store across the United States. Consumers consider this label to be an important attribute when making a purchasing decision and billions of dollars are spent annually on these products. While many consumers believe Natural foods are healthier, heavy reliance on that assumption is misguided as “Natural” has no formal legal definition—it’s merely defined pursuant to an FDA approved informal policy. Another important health attribute in a consumer’s purchasing decision is the presence of natural flavors in food. However, unlike the term Natural, FDA has promulgated legally binding regulations for natural flavors. These flavors are currently the fourth most common food ingredient listed on food labels. In reality, “natural flavors” are a far cry from what consumers might expect, as they can contain both artificial and synthetic chemicals (often used as processing aids). Nonetheless, without a legally binding Natural regulation, there has been little opportunity to contest the naturalness of natural flavors in the past. Recently, FDA has initiated a notification of request for comments on use of the term Natural, so an attempt to promulgate regulations may be underway. Thus, it is appropriate to consider where natural flavors will fall if binding regulations are set forth. This article looks at the Natural debate, its history, and model regulatory standards worth considering. Within that context, it also provides a critical discussion concerning a misunderstood, yet federally regulated, ingredient that our society so heavily consumes: natural flavors.

Natural additives and agricultural wastes in biopolymer formulations for food packaging.

PubMed

Valdés, Arantzazu; Mellinas, Ana Cristina; Ramos, Marina; Garrigós, María Carmen; Jiménez, Alfonso

2014-01-01

The main directions in food packaging research are targeted toward improvements in food quality and food safety. For this purpose, food packaging providing longer product shelf-life, as well as the monitoring of safety and quality based upon international standards, is desirable. New active packaging strategies represent a key area of development in new multifunctional materials where the use of natural additives and/or agricultural wastes is getting increasing interest. The development of new materials, and particularly innovative biopolymer formulations, can help to address these requirements and also with other packaging functions such as: food protection and preservation, marketing and smart communication to consumers. The use of biocomposites for active food packaging is one of the most studied approaches in the last years on materials in contact with food. Applications of these innovative biocomposites could help to provide new food packaging materials with improved mechanical, barrier, antioxidant, and antimicrobial properties. From the food industry standpoint, concerns such as the safety and risk associated with these new additives, migration properties and possible human ingestion and regulations need to be considered. The latest innovations in the use of these innovative formulations to obtain biocomposites are reported in this review. Legislative issues related to the use of natural additives and agricultural wastes in food packaging systems are also discussed.

Natural additives and agricultural wastes in biopolymer formulations for food packaging

NASA Astrophysics Data System (ADS)

Valdés, Arantzazu; Mellinas, Ana Cristina; Ramos, Marina; Garrigós, María Carmen; Jiménez, Alfonso

2014-02-01

The main directions in food packaging research are targeted towards improvements in food quality and food safety. For this purpose, food packaging providing longer product shelf-life, as well as the monitoring of safety and quality based upon international standards, is desirable. New active packaging strategies represent a key area of development in new multifunctional materials where the use of natural additives and/or agricultural wastes is getting increasing interest. The development of new materials, and particularly innovative biopolymer formulations, can help to address these requirements and also with other packaging functions such as: food protection and preservation, marketing and smart communication to consumers. The use of biocomposites for active food packaging is one of the most studied approaches in the last years on materials in contact with food. Applications of these innovative biocomposites could help to provide new food packaging materials with improved mechanical, barrier, antioxidant and antimicrobial properties. From the food industry standpoint, concerns such as the safety and risk associated with these new additives, migration properties and possible human ingestion and regulations need to be considered. The latest innovations in the use of these innovative formulations to obtain biocomposites are reported in this review. Legislative issues related to the use of natural additives and agricultural wastes in food packaging systems are also discussed.

Natural additives and agricultural wastes in biopolymer formulations for food packaging

PubMed Central

Valdés, Arantzazu; Mellinas, Ana Cristina; Ramos, Marina; Garrigós, María Carmen; Jiménez, Alfonso

2014-01-01

The main directions in food packaging research are targeted toward improvements in food quality and food safety. For this purpose, food packaging providing longer product shelf-life, as well as the monitoring of safety and quality based upon international standards, is desirable. New active packaging strategies represent a key area of development in new multifunctional materials where the use of natural additives and/or agricultural wastes is getting increasing interest. The development of new materials, and particularly innovative biopolymer formulations, can help to address these requirements and also with other packaging functions such as: food protection and preservation, marketing and smart communication to consumers. The use of biocomposites for active food packaging is one of the most studied approaches in the last years on materials in contact with food. Applications of these innovative biocomposites could help to provide new food packaging materials with improved mechanical, barrier, antioxidant, and antimicrobial properties. From the food industry standpoint, concerns such as the safety and risk associated with these new additives, migration properties and possible human ingestion and regulations need to be considered. The latest innovations in the use of these innovative formulations to obtain biocomposites are reported in this review. Legislative issues related to the use of natural additives and agricultural wastes in food packaging systems are also discussed. PMID:24790975

Brocaenols A-C: novel polyketides from a marine derived Penicillium brocae.

PubMed

Bugni, Tim S; Bernan, Valerie S; Greenstein, Michael; Janso, Jeffrey E; Maiese, William M; Mayne, Charles L; Ireland, Chris M

2003-03-07

Chemical investigation of a Penicillium brocae, obtained from a tissue sample of a Fijian Zyzyya sp. sponge, yielded two known diketopiperazines and three novel cytotoxic polyketides, brocaenols A-C. The brocaenols contain an unusual enolized oxepine lactone ring system that to the best of our knowledge is unprecedented in the literature. The structures were elucidated by using 2D-NMR methods including an INADEQUATE experiment. The absolute stereochemistry of brocaenol A was established by using a modified Mosher method. The taxonomy of the producing fungus was elucidated by using both morphological and rDNA sequence analysis.

Natural gums of plant origin as edible coatings for food industry applications.

PubMed

Saha, Anuradha; Tyagi, Shvetambri; Gupta, Rajinder K; Tyagi, Yogesh K

2017-12-01

Natural plant-based gums and their derivatives are widely utilized in food industries, however, their applications as edible coatings to extend fresh fruits and vegetable shelf-life has been explored recently. These natural polymeric polysaccharides have many advantages as compared to synthetic polymers, because they are biodegradable, nontoxic, economical and easily available in the environment. Natural gums can also be semi synthetically modified to produce derivatives, which can easily compete with the synthetic preservatives available on the food market. In this review, the recent developments in the use of natural gums and their derivatives as edible coatings have been explored and discussed.

Lessons from the synthetic chemist nature.

PubMed

Jürjens, Gerrit; Kirschning, Andreas; Candito, David A

2015-05-01

This conceptual review examines the ideal multistep synthesis from the perspective of nature. We suggest that besides step- and redox economies, one other key to efficiency is steady state processing with intermediates that are immediately transformed to the next intermediate when formed. We discuss four of nature's strategies (multicatalysis, domino reactions, iteration and compartmentation) that commonly proceed via short-lived intermediates and show that these strategies are also part of the chemist's portfolio. We particularly focus on compartmentation which in nature is found microscopically within cells (organelles) and between cells and on a molecular level on multiprotein scaffolds (e.g. in polyketide synthases) and demonstrate how compartmentation is manifested in modern multistep flow synthesis.

Prevention of fungal spoilage in food products using natural compounds: A review.

PubMed

Ribes, Susana; Fuentes, Ana; Talens, Pau; Barat, Jose Manuel

2017-04-10

The kingdom Fungi is the most important group of microorganism contaminating food commodities, and chemical additives are commonly used in the food industry to prevent fungal spoilage. However, the increasing consumer concern about synthetic additives has led to their substitution by natural compounds in foods. The current review provides an overview of using natural agents isolated from different sources (plants, animals, and microorganisms) as promising antifungal compounds, including information about their mechanism of action and their use in foods to preserve and prolong shelf life. Compounds derived from plants, chitosan, lactoferrin, and biocontrol agents (lactic acid bacteria, antagonistic yeast, and their metabolites) are able to control the decay caused by fungi in a wide variety of foods. Several strategies are employed to reduce the drawbacks of some antifungal agents, like their incorporation into oil-in-water emulsions and nanoemulsions, edible films and active packaging, and their combination with other natural preservatives. These strategies facilitate the addition of volatile agents into food products and, improve their antifungal effectiveness. Moreover, biological agents have been investigated as one of the most promising options in the control of postharvest decay. Numerous mechanisms of action have been elucidated and different approaches have been studied to enhance their antifungal effectiveness.

The polyketide synthase gene pks4 is essential for sexual development and regulates fruiting body morphology in Sordaria macrospora.

PubMed

Schindler, Daniel; Nowrousian, Minou

2014-07-01

Filamentous ascomycetes have long been known as producers of a variety of secondary metabolites, many of which have toxic effects on other organisms. However, the role of these metabolites in the biology of the fungi that produce them remains in most cases enigmatic. A major group of fungal secondary metabolites are polyketides. They are chemically diverse, but have in common that their chemical scaffolds are synthesized by polyketide synthases (PKSs). In a previous study, we analyzed development-dependent expression of pks genes in the filamentous ascomycete Sordaria macrospora. Here, we show that a deletion mutant of the pks4 gene is sterile, producing only protoperithecia but no mature perithecia, whereas overexpression of pks4 leads to enlarged, malformed fruiting bodies. Thus, correct expression levels of pks4 are essential for wild type-like perithecia formation. The predicted PKS4 protein has a domain structure that is similar to homologs in other fungi, but conserved residues of a methyl transferase domain present in other fungi are mutated in PKS4. Expression of several developmental genes is misregulated in the pks4 mutant. Surprisingly, the development-associated app gene is not downregulated in the mutant, in contrast to all other previously studied mutants with a block at the protoperithecial stage. Our data show that the polyketide synthase gene pks4 is essential for sexual development and plays a role in regulating fruiting body morphology. Copyright © 2014 Elsevier Inc. All rights reserved.

Bioactive compounds synthesized by non-ribosomal peptide synthetases and type-I polyketide synthases discovered through genome-mining and metagenomics.

PubMed

Nikolouli, Katerina; Mossialos, Dimitris

2012-08-01

Non-ribosomal peptide synthetases (NRPS) and type-I polyketide synthases (PKS-I) are multimodular enzymes involved in biosynthesis of oligopeptide and polyketide secondary metabolites produced by microorganisms such as bacteria and fungi. New findings regarding the mechanisms underlying NRPS and PKS-I evolution illustrate how microorganisms expand their metabolic potential. During the last decade rapid development of bioinformatics tools as well as improved sequencing and annotation of microbial genomes led to discovery of novel bioactive compounds synthesized by NRPS and PKS-I through genome-mining. Taking advantage of these technological developments metagenomics is a fast growing research field which directly studies microbial genomes or specific gene groups and their products. Discovery of novel bioactive compounds synthesized by NRPS and PKS-I will certainly be accelerated through metagenomics, allowing the exploitation of so far untapped microbial resources in biotechnology and medicine.

United States Department of Agriculture-Agricultural Research Service studies on polyketide toxins of Fusarium oxysporum f sp vasinfectum: potential targets for disease control.

PubMed

Bell, Alois A; Wheeler, Michael H; Liu, Jinggao; Stipanovic, Robert D; Puckhaber, Lorraine S; Orta, Heather

2003-01-01

A group of 133 isolates of the cotton wilt pathogen Fusarium oxysporum Schlecht f sp vasinfectum (Atk) Sny & Hans, representing five races and 20 vegetative compatibility groups within race 1 were used to determine the identity, biosynthetic regulation and taxonomic distribution of polyketide toxins produced by this pathogen. All isolates of F oxysporum f sp vasinfectum produced and secreted the nonaketide naphthazarin quinones, bikaverin and norbikaverin. Most isolates of race 1 (previously denoted as races 1, 2 and 6; and also called race A) also synthesized the heptaketide naphthoquinones, nectriafurone, anhydrofusarubin lactol and 5-O-methyljavanicin. Nine avirulent isolates of F oxysporum from Upland cotton roots, three isolates of race 3 of F oxysporum f sp vasinfectum, and four isolates of F oxysporum f sp vasinfectum from Australia, all of which previously failed to cause disease of Upland cotton (Gossypium hirsutum L) in stem-puncture assays, also failed to synthesize or secrete more than trace amounts of the heptaketide compounds. These results indicate that the heptaketides may have a unique role in the virulence of race 1 to Upland cotton. The synthesis of all polyketide toxins by ATCC isolate 24908 of F oxysporum f sp vasinfectum was regulated by pH, carbon/nitrogen ratios, and availability of calcium in media. Synthesis was greatest below pH 7.0 and increased progressively as carbon/nitrogen ratios were increased by decreasing the amounts of nitrogen added to media. The nonaketides were the major polyketides accumulated in synthetic media at pH 4.5 and below, whereas the heptaketides were predominant at pH 5.0 and above. The heptaketides were the major polyketides formed when 10 F oxysporum f sp vasinfectum race 1 isolates were grown on sterilized stems of Fusarium wilt-susceptible cotton cultivars, but these compounds were not produced on sorghum grain cultures. Both groups of polyketide toxins were apparently secreted by F oxysporum f sp vasinfectum

United States Department of Agriculture-Agricultural Research Service research on natural products for pest management.

PubMed

Duke, Stephen O; Baerson, Scott R; Dayan, Franck E; Rimando, Agnes M; Scheffler, Brian E; Tellez, Mario R; Wedge, David E; Schrader, Kevin K; Akey, David H; Arthur, Frank H; De Lucca, Anthony J; Gibson, Donna M; Harrison, Howard F; Peterson, Joseph K; Gealy, David R; Tworkoski, Thomas; Wilson, Charles L; Morris, J Brad

2003-01-01

Recent research of the Agricultural Research Service of USDA on the use of natural products to manage pests is summarized. Studies of the use of both phytochemicals and diatomaceous earth to manage insect pests are discussed. Chemically characterized compounds, such as a saponin from pepper (Capsicum frutescens L), benzaldehyde, chitosan and 2-deoxy-D-glucose are being studied as natural fungicides. Resin glycosides for pathogen resistance in sweet potato and residues of semi-tropical leguminous plants for nematode control are also under investigation. Bioassay-guided isolation of compounds with potential use as herbicides or herbicide leads is underway at several locations. New natural phytotoxin molecular target sites (asparagine synthetase and fructose-1,6-bisphosphate aldolase) have been discovered. Weed control in sweet potato and rice by allelopathy is under investigation. Molecular approaches to enhance allelopathy in sorghum are also being undertaken. The genes for polyketide synthases involved in production of pesticidal polyketide compounds in fungi are found to provide clues for pesticide discovery. Gene expression profiles in response to fungicides and herbicides are being generated as tools to understand more fully the mode of action and to rapidly determine the molecular target site of new, natural fungicides and herbicides.

The extent and nature of food promotion directed to children in Australian supermarkets.

PubMed

Chapman, Kathy; Nicholas, Penny; Banovic, Debbie; Supramaniam, Rajah

2006-12-01

The aim of this study was to describe the nature and amount of sales promotion use on food packaging in selected Australian supermarkets, specifically those directed at children through the use of premium offers, such as giveaways and competitions, and cartoon and movie character promotions. The study also examined the promotion of healthy versus unhealthy foods. Nine supermarkets located across the metropolitan area of Sydney, Australia were surveyed to assess the extent and nature of food promotion directed at children. The number and types of promotions were measured within seven food categories: sweet biscuits, snack foods, confectionery, chips/savoury snacks, cereals, dairy snacks and ice cream. Any foods that utilized promotional tactics were categorized as either healthy or unhealthy, according to set criteria. The study found that within the seven food categories between 9 and 35% of food products used promotional tactics. The use of television, movie celebrities and cartoon characters for promotion was most common, making up 75% of all promotions. Giveaways accounted for 13% of all promotions. When used, giveaways were commonly used in conjunction with another promotional method. Data from this study also confirmed that 82% of all food promotions were for unhealthy foods and only 18% were used to promote healthy foods. However, for dairy snacks and ice cream the majority of promotions, 99 and 65%, respectively, were healthier choices. This was the first study to describe the extent and nature of food promotions used in supermarkets. The promotion of unhealthy foods in supermarkets is common and is one of the many factors contributing to today's obesity promoting environment. Further research is required to determine the impact of food promotions on children's dietary intake, and to determine the most effective ways to restrict the promotion of unhealthy foods.

The role of natural color additives in food allergy.

PubMed

Lucas, C D; Hallagan, J B; Taylor, S L

2001-01-01

A critical evaluation of the available information demonstrates that reactions to natural color additives are rare. Studies of turmeric and carotenoid pigments administered in mixtures with other food colorings failed to definitely identify reactions to either color additive. For carotenoids, the one case report of an adverse reaction was not conclusive. An anaphylactic reaction to saffron does suggest an IgE-mediated reaction, but the high use of saffron as compared with this single report of an adverse reaction suggests that sensitivity to saffron is extremely rare. Numerous reports of reactions to grapes or grape products have been reported in the literature, but no reports of sensitivities to grape skin extract or grape color extract were found. In rare cases, annatto dye may provoke a severe, adverse reaction in individuals with an uncommon hypersensitivity, and may aggravate the symptoms of patients suffering from recurrent urticaria. In its long history of use, there has been only one reported case of anaphylaxis resulting from the ingestion of annatto. Studies designed to investigate the role of annatto in recurrent urticaria sufferers were limited due to the absence of double-blind challenge and placebo controls. A number of cases of adverse reactions to carmine following ingestion have been reported in the literature. These adverse reactions suggest an IgE-mediated hypersensitivity. In many of the reported cases, the cause of sensitization to carmine was topical exposure from the use of carmine-containing cosmetics or occupational exposure to carmine and not from ingestion of carmine-containing foods and beverages. Following sensitization, affected individuals would be sensitive to carmine and the amounts present in foods and beverages could elicit allergic reactions. It is not known whether all individuals with carmine sensitivity induced through topical use are sensitive to the ingestion of carmine in foods. However, reactions to carmine solely because

Recent advances in microencapsulation of natural sources of antimicrobial compounds used in food - A review.

PubMed

Castro-Rosas, Javier; Ferreira-Grosso, Carlos Raimundo; Gómez-Aldapa, Carlos Alberto; Rangel-Vargas, Esmeralda; Rodríguez-Marín, María Luisa; Guzmán-Ortiz, Fabiola Araceli; Falfan-Cortes, Reyna Nallely

2017-12-01

Food safety and microbiological quality are major priorities in the food industry. In recent years, there has been an increasing interest in the use of natural antimicrobials in food products. An ongoing challenge with natural antimicrobials is their degradation during food storage and/or processing, which reduces their antimicrobial activity. This creates the necessity for treatments that maintain their stability and/or activity when applied to food. Microencapsulation of natural antimicrobial compounds is a promising alternative once this technique consists of producing microparticles, which protect the encapsulated active substances. In other words, the material to be protected is embedded inside another material or system known as wall material. There are few reports in the literature about microencapsulation of antimicrobial compounds. These published articles report evidence of increased antimicrobial stability and activity when the antimicrobials are microencapsulated when compared to unprotected ones during storage. This review focuses mainly on natural sources of antimicrobial compounds and the methodological approach for encapsulating these natural compounds. Current data on the microencapsulation of antimicrobial compounds and their incorporation into food suggests that 1) encapsulation increases compound stability during storage and 2) encapsulation of antimicrobial compounds reduces their interaction with food components, preventing their inactivation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Natural resources - food nexus: food-related environmental footprints in the mediterranean countries.

PubMed

Lacirignola, Cosimo; Capone, Roberto; Debs, Philipp; El Bilali, Hamid; Bottalico, Francesco

2014-01-01

Immediate action is required in the Mediterranean to address environmental degradation that is mainly driven by consumption patterns. Increasing stress on biological and social systems is put by unsustainable consumption patterns. Food consumption patterns are important drivers of environment degradation. The objective of this review paper is to explore natural resources-food nexus in the Mediterranean region by highlighting the environmental footprints of the current consumption and production patterns. Secondary data from different sources such as FAOSTAT, the World Bank, Water Footprint Network (WFN), and Global Footprint Network were used to analyze the situation in 21 Mediterranean countries. The region faces many environmental challenges, e.g., land degradation, water scarcity, environment pollution, biodiversity loss, and climate change. The current consumption patterns imply high ecological, carbon, and water footprints of consumption and unfavorable national virtual-water balances. Food Balance Sheets data show that the contribution of vegetal and animal-based food product groups to food supply is variable among the Mediterranean countries. This has implications also in terms of the WF of food supply, which was calculated for Bosnia, Egypt, Italy, Morocco, and Turkey. The WF of the current diet resulted lower than that of the proposed Mediterranean one in the case of Italy. There is a strong scientific evidence supporting assumption that it is so also for other Mediterranean countries. The Mediterranean is characterized by a high resource use intensity that is further exacerbated by food losses and waste (FLW). In fact, FLW implies the loss of precious resources (water, land, energy) and inputs (fertilizers). Therefore, it is crucial to increase adherence to the traditional Mediterranean diet and to reduce FLW in order to foster transition to more sustainable food consumption patterns thus reducing pressure on the scarce resources of the Mediterranean

[Symbolism on "natural" in food].

PubMed

da Veiga Soares Carvalho, Maria Claudia; Luz, Madel Therezinha

2011-01-01

The incorporated senses represent a set of possibilities for future life able to build individual and collective identities. This work deepens the habitus, in Bourdieu's terms, associated with "natural" and fast-food styles, making an interpretative analysis of symbolic exchanges of elements reproduced in feeding practices. We believe that this bricolage arrangement of elements enables bartering and hybridism, marked by a tension that reflects the insecurity of technological innovations. The "natural" style represents an ideal of self-sustainability, non-polluting production, which faces the sanitary and ecologic crisis of the planet, against the large-scale industrialization and fast urbanization, defined as depredation factors of basic living conditions. The exchanges happen in a symbolic game connected with the global economic game, in which social actors make bets, illusio, according to particular intentions in concrete action. There is a chance to reformulate the rules of the game in the "game", although with a precarious balance of forces, in which the weaker side loses, an agent may have the possibility of not reproducing the pressures of globalized feeding, which is far from what might seem supernatural.

Identification and regulation of fusA, the polyketide synthase gene responsible for fusarin production in Fusarium fujikuroi.

PubMed

Díaz-Sánchez, Violeta; Avalos, Javier; Limón, M Carmen

2012-10-01

Fusarins are a class of mycotoxins of the polyketide family produced by different Fusarium species, including the gibberellin-producing fungus Fusarium fujikuroi. Based on sequence comparisons between polyketide synthase (PKS) enzymes for fusarin production in other Fusarium strains, we have identified the F. fujikuroi orthologue, called fusA. The participation of fusA in fusarin biosynthesis was demonstrated by targeted mutagenesis. Fusarin production is transiently stimulated by nitrogen availability in this fungus, a regulation paralleled by the fusA mRNA levels in the cell. Illumination of the cultures results in a reduction of the fusarin content, an effect partially explained by a high sensitivity of these compounds to light. Mutants of the fusA gene exhibit no external phenotypic alterations, including morphology and conidiation, except for a lack of the characteristic yellow and/or orange pigmentation of fusarins. Moreover, the fusA mutants are less efficient than the wild type at degrading cellophane on agar cultures, a trait associated with pathogenesis functions in Fusarium oxysporum. The fusA mutants, however, are not affected in their capacities to grow on plant tissues.

Wild inside: Urban wild boar select natural, not anthropogenic food resources.

PubMed

Stillfried, Milena; Gras, Pierre; Busch, Matthias; Börner, Konstantin; Kramer-Schadt, Stephanie; Ortmann, Sylvia

2017-01-01

Most wildlife species are urban avoiders, but some became urban utilizers and dwellers successfully living in cities. Often, they are assumed to be attracted into urban areas by easily accessible and highly energetic anthropogenic food sources. We macroscopically analysed stomachs of 247 wild boar (Sus scrofa, hereafter WB) from urban areas of Berlin and from the surrounding rural areas. From the stomach contents we determined as predictors of food quality modulus of fineness (MOF,), percentage of acid insoluble ash (AIA) and macronutrients such as amount of energy and percentage of protein, fat, fibre and starch. We run linear mixed models to test: (1) differences in the proportion of landscape variables, (2) differences of nutrients consumed in urban vs. rural WB and (3) the impact of landscape variables on gathered nutrients. We found only few cases of anthropogenic food in the qualitative macroscopic analysis. We categorized the WB into five stomach content categories but found no significant difference in the frequency of those categories between urban and rural WB. The amount of energy was higher in stomachs of urban WB than in rural WB. The analysis of landscape variables revealed that the energy of urban WB increased with increasing percentage of sealing, while an increased human density resulted in poor food quality for urban and rural WB. Although the percentage of protein decreased in areas with a high percentage of coniferous forests, the food quality increased. High percentage of grassland decreased the percentage of consumed fat and starch and increased the percentage of fibre, while a high percentage of agricultural areas increased the percentage of consumed starch. Anthropogenic food such as garbage might serve as fallback food when access to natural resources is limited. We infer that urban WB forage abundant, natural resources in urban areas. Urban WB might use anthropogenic resources (e.g. garbage) if those are easier to exploit and more abundant

Wild inside: Urban wild boar select natural, not anthropogenic food resources

PubMed Central

Stillfried, Milena; Gras, Pierre; Busch, Matthias; Börner, Konstantin; Kramer-Schadt, Stephanie; Ortmann, Sylvia

2017-01-01

Most wildlife species are urban avoiders, but some became urban utilizers and dwellers successfully living in cities. Often, they are assumed to be attracted into urban areas by easily accessible and highly energetic anthropogenic food sources. We macroscopically analysed stomachs of 247 wild boar (Sus scrofa, hereafter WB) from urban areas of Berlin and from the surrounding rural areas. From the stomach contents we determined as predictors of food quality modulus of fineness (MOF,), percentage of acid insoluble ash (AIA) and macronutrients such as amount of energy and percentage of protein, fat, fibre and starch. We run linear mixed models to test: (1) differences in the proportion of landscape variables, (2) differences of nutrients consumed in urban vs. rural WB and (3) the impact of landscape variables on gathered nutrients. We found only few cases of anthropogenic food in the qualitative macroscopic analysis. We categorized the WB into five stomach content categories but found no significant difference in the frequency of those categories between urban and rural WB. The amount of energy was higher in stomachs of urban WB than in rural WB. The analysis of landscape variables revealed that the energy of urban WB increased with increasing percentage of sealing, while an increased human density resulted in poor food quality for urban and rural WB. Although the percentage of protein decreased in areas with a high percentage of coniferous forests, the food quality increased. High percentage of grassland decreased the percentage of consumed fat and starch and increased the percentage of fibre, while a high percentage of agricultural areas increased the percentage of consumed starch. Anthropogenic food such as garbage might serve as fallback food when access to natural resources is limited. We infer that urban WB forage abundant, natural resources in urban areas. Urban WB might use anthropogenic resources (e.g. garbage) if those are easier to exploit and more abundant

Uncovering the formation and selection of benzylmalonyl-CoA from the biosynthesis of splenocin and enterocin reveals a versatile way to introduce amino acids into polyketide carbon scaffolds.

PubMed

Chang, Chenchen; Huang, Rong; Yan, Yan; Ma, Hongmin; Dai, Zheng; Zhang, Benying; Deng, Zixin; Liu, Wen; Qu, Xudong

2015-04-01

Selective modification of carbon scaffolds via biosynthetic engineering is important for polyketide structural diversification. Yet, this scope is currently restricted to simple aliphatic groups due to (1) limited variety of CoA-linked extender units, which lack aromatic structures and chemical reactivity, and (2) narrow acyltransferase (AT) specificity, which is limited to aliphatic CoA-linked extender units. In this report, we uncovered and characterized the first aromatic CoA-linked extender unit benzylmalonyl-CoA from the biosynthetic pathways of splenocin and enterocin in Streptomyces sp. CNQ431. Its synthesis employs a deamination/reductive carboxylation strategy to convert phenylalanine into benzylmalonyl-CoA, providing a link between amino acid and CoA-linked extender unit synthesis. By characterization of its selection, we further validated that AT domains of splenocin, and antimycin polyketide synthases are able to select this extender unit to introduce the phenyl group into their dilactone scaffolds. The biosynthetic machinery involved in the formation of this extender unit is highly versatile and can be potentially tailored for tyrosine, histidine and aspartic acid. The disclosed aromatic extender unit, amino acid-oriented synthetic pathway, and aromatic-selective AT domains provides a systematic breakthrough toward current knowledge of polyketide extender unit formation and selection, and also opens a route for further engineering of polyketide carbon scaffolds using amino acids.

Consumer exposures to anthocyanins from colour additives, colouring foodstuffs and from natural occurrence in foods.

PubMed

Tennant, David R; Klingenberg, Andreas

2016-06-01

Anthocyanins are responsible for the red/blue colour of grapes, currants, and other fruits and vegetables. They may also be extracted for use as colour additives (E163) or concentrated for use as colouring foods. Consumer exposures have been assessed using data on natural occurrence, use levels and frequencies from food manufacturers and European food consumption data. Intakes from natural occurrence can be up to 4 mg kg bw(-1) day(-1) at the mean and up to 17 mg kg bw(-1) day(-1) for children who are high level consumers of red/black berries and small fruits. High-level intakes for children from food colour and colouring food applications lie in the range 0.3-6.3 mg kg bw(-1) day(-1) and for adults at 0.6-2.8 mg kg bw(-1) day(-1). Exposures from food colour use and colouring foods separately or combined are therefore lower than those from natural occurrence in foods.

21 CFR 110.110 - Natural or unavoidable defects in food for human use that present no health hazard.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Natural or unavoidable defects in food for human... PRACTICE IN MANUFACTURING, PACKING, OR HOLDING HUMAN FOOD Defect Action Levels § 110.110 Natural or... natural or unavoidable defects to the lowest level currently feasible. (d) The mixing of a food containing...

Functionality of liquid smoke as an all-natural antimicrobial in food preservation.

PubMed

Lingbeck, Jody M; Cordero, Paola; O'Bryan, Corliss A; Johnson, Michael G; Ricke, Steven C; Crandall, Philip G

2014-06-01

The smoking of foods, especially meats, has been used as a preservation technique for centuries. Today, smoking methods often involve the use of wood smoke condensates, commonly known as liquid smoke. Liquid smoke is produced by condensing wood smoke created by the pyrolysis of sawdust or wood chips followed by removal of the carcinogenic polyaromatic hydrocarbons. The main products of wood pyrolysis are phenols, carbonyls and organic acids which are responsible for the flavor, color and antimicrobial properties of liquid smoke. Several common food-borne pathogens such as Listeria monocytogenes, Salmonella, pathogenic Escherichia coli and Staphylococcus have shown sensitivity to liquid smoke in vitro and in food systems. Therefore liquid smoke has potential for use as an all-natural antimicrobial in commercial applications where smoke flavor is desired. This review will cover the application and effectiveness of liquid smoke and fractions of liquid smoke as an all-natural food preservative. This review will be valuable for the industrial and research communities in the food science and technology areas. Copyright © 2014. Published by Elsevier Ltd.

Natural Resources – Food Nexus: Food-Related Environmental Footprints in the Mediterranean Countries

PubMed Central

Lacirignola, Cosimo; Capone, Roberto; Debs, Philipp; El Bilali, Hamid; Bottalico, Francesco

2014-01-01

Immediate action is required in the Mediterranean to address environmental degradation that is mainly driven by consumption patterns. Increasing stress on biological and social systems is put by unsustainable consumption patterns. Food consumption patterns are important drivers of environment degradation. The objective of this review paper is to explore natural resources-food nexus in the Mediterranean region by highlighting the environmental footprints of the current consumption and production patterns. Secondary data from different sources such as FAOSTAT, the World Bank, Water Footprint Network (WFN), and Global Footprint Network were used to analyze the situation in 21 Mediterranean countries. The region faces many environmental challenges, e.g., land degradation, water scarcity, environment pollution, biodiversity loss, and climate change. The current consumption patterns imply high ecological, carbon, and water footprints of consumption and unfavorable national virtual-water balances. Food Balance Sheets data show that the contribution of vegetal and animal-based food product groups to food supply is variable among the Mediterranean countries. This has implications also in terms of the WF of food supply, which was calculated for Bosnia, Egypt, Italy, Morocco, and Turkey. The WF of the current diet resulted lower than that of the proposed Mediterranean one in the case of Italy. There is a strong scientific evidence supporting assumption that it is so also for other Mediterranean countries. The Mediterranean is characterized by a high resource use intensity that is further exacerbated by food losses and waste (FLW). In fact, FLW implies the loss of precious resources (water, land, energy) and inputs (fertilizers). Therefore, it is crucial to increase adherence to the traditional Mediterranean diet and to reduce FLW in order to foster transition to more sustainable food consumption patterns thus reducing pressure on the scarce resources of the Mediterranean

Protein-Protein Interactions, Not Substrate Recognition, Dominate the Turnover of Chimeric Assembly Line Polyketide Synthases*

PubMed Central

Klaus, Maja; Ostrowski, Matthew P.; Austerjost, Jonas; Robbins, Thomas; Lowry, Brian; Cane, David E.; Khosla, Chaitan

2016-01-01

The potential for recombining intact polyketide synthase (PKS) modules has been extensively explored. Both enzyme-substrate and protein-protein interactions influence chimeric PKS activity, but their relative contributions are unclear. We now address this issue by studying a library of 11 bimodular and 8 trimodular chimeric PKSs harboring modules from the erythromycin, rifamycin, and rapamycin synthases. Although many chimeras yielded detectable products, nearly all had specific activities below 10% of the reference natural PKSs. Analysis of selected bimodular chimeras, each with the same upstream module, revealed that turnover correlated with the efficiency of intermodular chain translocation. Mutation of the acyl carrier protein (ACP) domain of the upstream module in one chimera at a residue predicted to influence ketosynthase-ACP recognition led to improved turnover. In contrast, replacement of the ketoreductase domain of the upstream module by a paralog that produced the enantiomeric ACP-bound diketide caused no changes in processing rates for each of six heterologous downstream modules compared with those of the native diketide. Taken together, these results demonstrate that protein-protein interactions play a larger role than enzyme-substrate recognition in the evolution or design of catalytically efficient chimeric PKSs. PMID:27246853

Leadership Learning Opportunities in Agriculture, Food, and Natural Resources Education: The Role of The Teacher

ERIC Educational Resources Information Center

McKim, Aaron J.; Pauley, C. M.; Velez, Jonathan J.; Sorensen, Tyson J.

2017-01-01

Learning environments combining agriculture, food, natural resources, and leadership knowledge and skills are increasingly essential in preparing students for future success. School-based agricultural education offers a premier context in which to teach leadership within agriculture, food, and natural resources curriculum. However, providing…

In Vitro Investigation of Crosstalk between Fatty Acid and Polyketide Synthases in the Andrimid Biosynthetic Assembly Line.

PubMed

Ishikawa, Fumihiro; Sugimoto, Hiroyasu; Kakeya, Hideaki

2016-11-17

Andrimid (Adm) synthase, which belongs to the type II system of enzymes, produces Adm in Pantoea agglomerans. The adm biosynthetic gene cluster lacks canonical acyltransferases (ATs) to load the malonyl group to acyl carrier proteins (ACPs), thus suggesting that a malonyl-CoA ACP transacylase (MCAT) from the fatty acid synthase (FAS) complex provides the essential AT activity in Adm biosynthesis. Here we report that an MCAT is essential for catalysis of the transacylation of malonate from malonyl-CoA to AdmA polyketide synthase (PKS) ACP in vitro. Catalytic self-malonylation of AdmA (PKS ACP) was not observed in reactions without MCAT, although many type II PKS ACPs are capable of catalyzing self-acylation. This lack of self-malonylation was explained by amino acid sequence analysis of the AdmA PKS ACP and the type II PKS ACPs. The results show that MCAT from the organism's FAS complex can provide the missing AT activity in trans, thus suggesting a protein-protein interaction between the fatty acid and polyketide synthases in the Adm assembly line. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The secreted polyketide boydone A is responsible for the anti-Staphylococcus aureus activity of Scedosporium boydii.

PubMed

Staerck, Cindy; Landreau, Anne; Herbette, Gaëtan; Roullier, Catherine; Bertrand, Samuel; Siegler, Benjamin; Larcher, Gérald; Bouchara, Jean-Philippe; Fleury, Maxime J J

2017-12-01

Usually living as a soil saprophyte, the filamentous fungus Scedosporium boydii may also cause various infections in human. Particularly, it is one of the major causative agents of fungal colonization of the airways in patients with cystic fibrosis (CF). To compete with other microorganisms in the environment, fungi have evolved sophisticated strategies, including the production of secondary metabolites with antimicrobial activity that may also help them to establish successfully within the respiratory tract of receptive hosts. Here, the culture filtrate from a human pathogenic strain of S. boydii was investigated searching for an antibacterial activity, mainly against the major CF bacterial pathogens. A high antibacterial activity against Staphylococcus aureus, including methicillin-resistant strains of this species, was observed. Bio-guided fractionation and analysis of the active fractions by nuclear magnetic resonance or by high-performance liquid chromatography and high-resolution electrospray ionization-mass spectrometry allowed us to identify boydone A as responsible for this antibacterial activity. Together, these results suggest that this six-membered cyclic polyketide could be one of the virulence factors of the fungus. Genes involved in the synthesis of this secreted metabolite are currently being identified in order to confirm the role of this polyketide in pathogenesis. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Improvement of FK506 Production in Streptomyces tsukubaensis by Genetic Enhancement of the Supply of Unusual Polyketide Extender Units via Utilization of Two Distinct Site-Specific Recombination Systems

PubMed Central

Chen, Dandan; Zhang, Qi; Zhang, Qinglin; Cen, Peilin

2012-01-01

FK506 is a potent immunosuppressant that has a wide range of clinical applications. Its 23-member macrocyclic scaffold, mainly with a polyketide origin, features two methoxy groups at C-13 and C-15 and one allyl side chain at C-21, due to the region-specific incorporation of two unusual extender units derived from methoxymalonyl-acyl carrier protein (ACP) and allylmalonyl-coenzyme A (CoA), respectively. Whether their intracellular formations can be a bottleneck for FK506 production remains elusive. In this study, we report the improvement of FK506 yield in the producing strain Streptomyces tsukubaensis by the duplication of two sets of pathway-specific genes individually encoding the biosyntheses of these two extender units, thereby providing a promising approach to generate high-FK506-producing strains via genetic manipulation. Taking advantage of the fact that S. tsukubaensis is amenable to two actinophage (ΦC31 and VWB) integrase-mediated recombination systems, we genetically enhanced the biosyntheses of methoxymalonyl-ACP and allylmalonyl-CoA, as indicated by transcriptional analysis. Together with the optimization of glucose supplementation, the maximal FK506 titer eventually increased by approximately 150% in comparison with that of the original strain. The strategy of engineering the biosynthesis of unusual extender units described here may be applicable to improving the production of other polyketide or nonribosomal peptide natural products that contain pathway-specific building blocks. PMID:22582065

Nonribosomal peptides and polyketides of Burkholderia: new compounds potentially implicated in biocontrol and pharmaceuticals.

PubMed

Esmaeel, Qassim; Pupin, Maude; Jacques, Philippe; Leclère, Valérie

2017-05-25

Bacteria belonging to the genus Burkholderia live in various ecological niches and present a significant role in the environments through the excretion of a wide variety of secondary metabolites including modular nonribosomal peptides (NRPs) and polyketides (PKs). These metabolites represent a widely distributed biomedically and biocontrol important class of natural products including antibiotics, siderophores, and anticancers as well as biopesticides that are considered as a novel source that can be used to defend ecological niche from competitors and to promote plant growth. The aim of this review is to present all NRPs produced or potentially produced by strains of Burkholderia, as NRPs represent a major source of active compounds implicated in biocontrol. The review is a compilation of results from a large screening we have performed on 48 complete sequenced genomes available in NCBI to identify NRPS gene clusters, and data found in the literature mainly because some interesting compounds are produced by strains not yet sequenced. In addition to NRPs, hybrids NRPs/PKs are also included. Specific features about biosynthetic gene clusters and structures of the modular enzymes responsible for the synthesis, the biological activities, and the potential uses in agriculture and pharmaceutical of NRPs and hybrids NRPs/PKs will also be discussed.

Disseminins and Spiciferone Analogues: Polyketide-Derived Metabolites from a Fungicolous Isolate of Pestalotiopsis disseminata.

PubMed

Hwang, In Hyun; Swenson, Dale C; Gloer, James B; Wicklow, Donald T

2016-03-25

Seven new polyketide metabolites (disseminins A-E, 1-5, and spiciferones D and E, 7 and 8) were obtained from cultures of a fungicolous isolate of Pestalotiopsis disseminata (NRRL 62562), together with a related compound (6) previously known only as a semisynthetic product. Structures were determined mainly by analysis of HRMS and NMR data. Biogenetically related compounds 1 and 2 possess uncommon bis-tetrahydrofuran and dioxabicyclo[3.2.1]octane ring systems, respectively. X-ray crystallographic analysis of the p-bromobenzoate derivative of 1 confirmed the structure and enabled assignment of its absolute configuration.

Biosynthesis and molecular genetics of polyketides in marine dinoflagellates.

PubMed

Kellmann, Ralf; Stüken, Anke; Orr, Russell J S; Svendsen, Helene M; Jakobsen, Kjetill S

2010-03-31

Marine dinoflagellates are the single most important group of algae that produce toxins, which have a global impact on human activities. The toxins are chemically diverse, and include macrolides, cyclic polyethers, spirolides and purine alkaloids. Whereas there is a multitude of studies describing the pharmacology of these toxins, there is limited or no knowledge regarding the biochemistry and molecular genetics involved in their biosynthesis. Recently, however, exciting advances have been made. Expressed sequence tag sequencing studies have revealed important insights into the transcriptomes of dinoflagellates, whereas other studies have implicated polyketide synthase genes in the biosynthesis of cyclic polyether toxins, and the molecular genetic basis for the biosynthesis of paralytic shellfish toxins has been elucidated in cyanobacteria. This review summarises the recent progress that has been made regarding the unusual genomes of dinoflagellates, the biosynthesis and molecular genetics of dinoflagellate toxins. In addition, the evolution of these metabolic pathways will be discussed, and an outlook for future research and possible applications is provided.

Biosynthesis and Molecular Genetics of Polyketides in Marine Dinoflagellates

PubMed Central

Kellmann, Ralf; Stüken, Anke; Orr, Russell J. S.; Svendsen, Helene M.; Jakobsen, Kjetill S.

2010-01-01

Marine dinoflagellates are the single most important group of algae that produce toxins, which have a global impact on human activities. The toxins are chemically diverse, and include macrolides, cyclic polyethers, spirolides and purine alkaloids. Whereas there is a multitude of studies describing the pharmacology of these toxins, there is limited or no knowledge regarding the biochemistry and molecular genetics involved in their biosynthesis. Recently, however, exciting advances have been made. Expressed sequence tag sequencing studies have revealed important insights into the transcriptomes of dinoflagellates, whereas other studies have implicated polyketide synthase genes in the biosynthesis of cyclic polyether toxins, and the molecular genetic basis for the biosynthesis of paralytic shellfish toxins has been elucidated in cyanobacteria. This review summarises the recent progress that has been made regarding the unusual genomes of dinoflagellates, the biosynthesis and molecular genetics of dinoflagellate toxins. In addition, the evolution of these metabolic pathways will be discussed, and an outlook for future research and possible applications is provided. PMID:20479965

Kibdelones: novel anticancer polyketides from a rare Australian actinomycete.

PubMed

Ratnayake, Ranjala; Lacey, Ernest; Tennant, Shaun; Gill, Jennifer H; Capon, Robert J

2007-01-01

The kibdelones are a novel family of bioactive heterocyclic polyketides produced by a rare soil actinomycete, Kibdelosporangium sp. (MST-108465). Complete relative stereostructures were assigned to kibdelones A-C (1-3), kibdelone B rhamnoside (5), 13-oxokibdelone A (7), and 25-methoxy-24-oxokibdelone C (8) on the basis of detailed spectroscopic analysis and chemical interconversion, as well as mechanistic and biosynthetic considerations. Under mild conditions, kibdelones B (2) and C (3) undergo a facile equilibration to kibdelones A-C (1-3), while kibdelone B rhamnoside (5) equilibrates to a mixture of kibdelone A-C rhamnosides (4-6). A plausible mechanism for this equilibration is proposed and involves air oxidation, quinone/hydroquinone redox transformations, and a choreographed sequence of keto/enol tautomerizations that aromatize ring C via a quinone methide intermediate. Kibdelones exhibit potent and selective cytotoxicity against a panel of human tumor cell lines and display significant antibacterial and nematocidal activity.

Reported attitudes and beliefs toward soy food consumption of soy consumers versus nonconsumers in natural foods or mainstream grocery stores.

PubMed

Schyver, Tamara; Smith, Chery

2005-01-01

To examine the attitudes and beliefs of soy foods consumers (SCs) versus nonconsumers (NCs). Seven focus groups were conducted. Mainstream or natural foods grocery stores. Fifty-three participants, ages 18 to 91 years. Focus groups included discussions on lifestyle practices, beliefs about soy, conversion to soy consumption, and suggestions on how to increase soy consumption. Common themes were identified, coded, and compared using NVivo computer software. Barriers to soy consumption included soy's image, a lack of familiarity with how to prepare soy foods, and a perception that soy foods were an inadequate flavor substitute for animal-based products. SCs' conversion to regular consumption was initiated by food intolerances, an increased interest in health, or an adoption of a vegetarian or natural foods lifestyle and was sustained because they enjoyed the flavor. Many participants did not know why soy was considered healthful, whereas others identified it as "heart healthy," a source of protein, and good for women's health. Some SCs had become concerned regarding the controversy surrounding breast cancer and soy consumption. Improving soy's image and educating consumers on its preparation could increase soy consumption.

Natural Products Version 2.0: Connecting Genes to Molecules

PubMed Central

Walsh, Christopher T.; Fischbach, Michael A.

2009-01-01

Natural products have played a prominent role in the history of organic chemistry, and they continue to be important as drugs, biological probes, and targets of study for synthetic and analytical chemists. In this perspective, we explore how connecting Nature’s small molecules to the genes that encode them has sparked a renaissance in natural product research, focusing primarily on the biosynthesis of polyketides and nonribosomal peptides. We survey monomer biogenesis, coupling chemistries from templated and non-templated pathways, and the broad set of tailoring reactions and hybrid pathways that give rise to the diverse scaffolds and functionalization patterns of natural products. We conclude by considering two questions: What would it take to find all natural product scaffolds? What kind of scientists will be studying natural products in the future? PMID:20121095

Anthropogenic and natural sources of acidity and metals and their influence on the structure of stream food webs.

PubMed

Hogsden, Kristy L; Harding, Jon S

2012-03-01

We compared food web structure in 20 streams with either anthropogenic or natural sources of acidity and metals or circumneutral water chemistry in New Zealand. Community and diet analysis indicated that mining streams receiving anthropogenic inputs of acidic and metal-rich drainage had much simpler food webs (fewer species, shorter food chains, less links) than those in naturally acidic, naturally high metal, and circumneutral streams. Food webs of naturally high metal streams were structurally similar to those in mining streams, lacking fish predators and having few species. Whereas, webs in naturally acidic streams differed very little from those in circumneutral streams due to strong similarities in community composition and diets of secondary and top consumers. The combined negative effects of acidity and metals on stream food webs are clear. However, elevated metal concentrations, regardless of source, appear to play a more important role than acidity in driving food web structure. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluating natural antimicrobials for food application, in natural antimicrobials for food safety and quality

USDA-ARS?s Scientific Manuscript database

The microflora of foods is of practical significance to producers, processors and consumers. Food manufacturers and distributors are responding to consumers’ demand for food products that are safe, fresher and convenient for use. In some cases foods may be improperly processed and/or contaminated wi...

A Natural Experiment: Using Immersive Technologies to Study the Impact of "All-Natural" Labeling on Perceived Food Quality, Nutritional Content, and Liking.

PubMed

Liu, Rebecca; Hooker, Neal H; Parasidis, Efthimios; Simons, Christopher T

2017-03-01

The "all-natural" label is used extensively in the United States. At many point-of-purchase locations, employed servers provide food samples and call out specific label information to influence consumers' purchase decisions. Despite these ubiquitous practices, it is unclear what information is conveyed to consumers by the all-natural label or how it impacts judgments of perceived food quality, nutritional content, and acceptance. We used a novel approach incorporating immersive technology to simulate a virtual in-store sampling scenario where consumers were asked by a server to evaluate identical products with only one being labeled all-natural. Another condition evaluated the impact of the in-store server additionally emphasizing the all-natural status of one sample. Results indicated the all-natural label significantly improved consumer's perception of product quality and nutritional content, but not liking or willingness to pay, when compared to the regular sample. With the simple emphasis of the all-natural claim by the in-store server, these differences in quality and nutritional content became even more pronounced, and willingness to pay increased significantly by an average of 8%. These results indicate that in a virtual setting consistent with making food purchases, an all-natural front-of-pack label improves consumer perceptions of product quality and nutritional content. In addition, information conveyed to consumers by employed servers has a further, substantial impact on these variables suggesting that consumers are highly susceptible to social influence at the point of purchase. © 2017 Institute of Food Technologists®.

Functional Promiscuity of Two Divergent Paralogs of Type III Plant Polyketide Synthases1

PubMed Central

Pandith, Shahzad A.; Dhar, Niha; Bhat, Wajid Waheed; Kushwaha, Manoj; Gupta, Ajai P.; Shah, Manzoor A.; Vishwakarma, Ram

2016-01-01

Plants effectively defend themselves against biotic and abiotic stresses by synthesizing diverse secondary metabolites, including health-protective flavonoids. These display incredible chemical diversity and ubiquitous occurrence and confer impeccable biological and agricultural applications. Chalcone synthase (CHS), a type III plant polyketide synthase, is critical for flavonoid biosynthesis. It catalyzes acyl-coenzyme A thioesters to synthesize naringenin chalcone through a polyketidic intermediate. The functional divergence among the evolutionarily generated members of a gene family is pivotal in driving the chemical diversity. Against this backdrop, this study was aimed to functionally characterize members of the CHS gene family from Rheum emodi, an endangered and endemic high-altitude medicinal herb of northwestern Himalayas. Two full-length cDNAs (1,179 bp each), ReCHS1 and ReCHS2, encoding unique paralogs were isolated and characterized. Heterologous expression and purification in Escherichia coli, bottom-up proteomic characterization, high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry analysis, and enzyme kinetic studies using five different substrates confirmed their catalytic potential. Phylogenetic analysis revealed the existence of higher synonymous mutations in the intronless divergents of ReCHS. ReCHS2 displayed significant enzymatic efficiency (Vmax/Km) with different substrates. There were significant spatial and altitudinal variations in messenger RNA transcript levels of ReCHSs correlating positively with metabolite accumulation. Furthermore, the elicitations in the form of methyl jasmonate, salicylic acid, ultraviolet B light, and wounding, chosen on the basis of identified cis-regulatory promoter elements, presented considerable differences in the transcript profiles of ReCHSs. Taken together, our results demonstrate differential propensities of CHS paralogs in terms of the accumulation of flavonoids and

Applications of natural zeolites on agriculture and food production.

PubMed

Eroglu, Nazife; Emekci, Mevlut; Athanassiou, Christos G

2017-08-01

Zeolites are crystalline hydrated aluminosilicates with remarkable physical and chemical properties, which include losing and receiving water in a reverse way, adsorbing molecules that act as molecular sieves, and replacing their constituent cations without structural change. The commercial production of natural zeolites has accelerated during the last 50 years. The Structure Commission of the International Zeolite Association recorded more than 200 zeolites, which currently include more than 40 naturally occurring zeolites. Recent findings have supported their role in stored-pest management as inert dust applications, pesticide and fertilizer carriers, soil amendments, animal feed additives, mycotoxin binders and food packaging materials. There are many advantages of inert dust application, including low cost, non-neurotoxic action, low mammalian toxicity and safety for human consumption. The latest consumer trends and government protocols have shifted toward organic origin materials to replace synthetic chemical products. In the present review, we summarize most of the main uses of zeolites in food and agruculture, along with the with specific paradigms that illustrate their important role. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Generation of semicarbazide from natural azine development in foods, followed by reaction with urea compounds.

PubMed

Abernethy, Grant A

2015-01-01

This paper proposes a mechanism to explain the trace levels of natural semicarbazide occasionally observed in foods. The analytical derivative of semicarbazide, 2-nitrobenzaldehyde semicarbazone, is often measured as a metabolite marker to detect the widely banned antibiotic nitrofurazone. However, this marker is not specific as semicarbazide may be present in foods for several reasons other than exposure to nitrofurazone. In some cases, an entirely natural origin of semicarbazide is suspected, although up until now there was no explanation about how semicarbazide could occur naturally. In this work, semicarbazide is proposed as being generated from natural food compounds via an azine intermediate. Hydrazine, in the form of azines or hydrazones, may be generated in dilute aqueous solution from the natural food compounds ammonia, hydrogen peroxide and acetone, following known oxidation chemistry. When this mixture was prepared in the presence of ureas such as allantoin, urea, biuret or hydroxyurea, and then analysed by the standard method for the determination of semicarbazide, 2-nitrobenzaldehyde semicarbazone was detected. 2-Nitrobenzaldehyde aldazine was also found, and it may be a general marker for azines in foods. This proposal, that azine formation is central to semicarbazide development, provides a convergence of the published mechanisms for semicarbazide. The reaction starts with hydrogen peroxide, peracetic acid, atmospheric oxygen or hypochlorite; generates hydrazine either by an oxaziridine intermediate or via the chlorination of ammonia; and then either route may converge on azine formation, followed by reaction with a urea compound. Additionally, carbamate ion may speculatively generate semicarbazide by reaction with hydrazine, which might be a significant route in the case of the hypochlorite treatment of foods or food contact surfaces. Significantly, detection of 2-nitrobenzaldehyde semicarbazone may be somewhat artefactual because semicarbazide can

Polyketide derivatives from a marine-sponge-associated fungus Pestalotiopsis heterocornis.

PubMed

Lei, Hui; Lin, Xiuping; Han, Li; Ma, Jian; Dong, Kailin; Wang, Xingbo; Zhong, Jialiang; Mu, Yu; Liu, Yonghong; Huang, Xueshi

2017-10-01

Twelve previously undescribed polyketide derivatives, heterocornols A-L, and seven known analogues were isolated from a culture of the fungus Pestalotiopsis heterocornis associated with sponge. Their structures were elucidated by a comprehensive spectroscopic data analysis and CD Cotton effects. These compounds were evaluated for cytotoxic and antibacterial activities in vitro. Among them, heterocornols A-C, F-H, methyl-(2-formyl-3-hydroxyphenyl)propanoate, agropyrenol, and vaccinol G exhibited cytotoxicities against four human cancer cell lines with IC 50 values 15-100 μM, and they also showed antibacterial activities against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with MIC values ranging from 25 to 100 μg/mL. Moreover, compounds heterocornol C, heterocornol G, agropyrenol, and vaccinol G showed weak antifungal activities against Candida parapsilosis and Cryptococcus neoformans with MIC values 100 μg/mL. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Natural Component-Based Oxygen Indicator with In-Pack Activation for Intelligent Food Packaging.

PubMed

Won, Keehoon; Jang, Nan Young; Jeon, Junsu

2016-12-28

Intelligent food packaging can provide consumers with reliable and correct information on the quality and safety of packaged foods. One of the key constituents in intelligent packaging is a colorimetric oxygen indicator, which is widely used to detect oxygen gas involved in food spoilage by means of a color change. Traditional oxygen indicators consisting of redox dyes and strong reducing agents have two major problems: they must be manufactured and stored under anaerobic conditions because air depletes the reductant, and their components are synthetic and toxic. To address both of these serious problems, we have developed a natural component-based oxygen indicator characterized by in-pack activation. The conventional oxygen indicator composed of synthetic and artificial components was redesigned using naturally occurring compounds (laccase, guaiacol, and cysteine). These natural components were physically separated into two compartments by a fragile barrier. Only when the barrier was broken were all of the components mixed and the function as an oxygen indicator was begun (i.e., in-pack activation). Depending on the component concentrations, the natural component-based oxygen indicator exhibited different response times and color differences. The rate of the color change was proportional to the oxygen concentration. This novel colorimetric oxygen indicator will contribute greatly to intelligent packaging for healthier and safer foods.

Opportunities and Challenges for Natural Products as Novel Antituberculosis Agents.

PubMed

Farah, Shrouq I; Abdelrahman, Abd Almonem; North, E Jeffrey; Chauhan, Harsh

2016-01-01

Current tuberculosis (TB) treatment suffers from complexity of the dosage regimens, length of treatment, and toxicity risks. Many natural products have shown activity against drug-susceptible, drug-resistant, and latent/dormant Mycobacterium tuberculosis, the pathogen responsible for TB infections. Natural sources, including plants, fungi, and bacteria, provide a rich source of chemically diverse compounds equipped with unique pharmacological, pharmacokinetic, and pharmacodynamic properties. This review focuses on natural products as starting points for the discovery and development of novel anti-TB chemotherapy and classifies them based on their chemical nature. The classes discussed are divided into alkaloids, chalcones, flavonoids, peptides, polyketides, steroids, and terpenes. This review also highlights the importance of collaboration between phytochemistry, medicinal chemistry, and physical chemistry, which is very important for the development of these natural compounds.

Indigo Dye Derived from Indigofera Tinctoria as Natural Food Colorant

NASA Astrophysics Data System (ADS)

Wahyuningsih, S.; Ramelan, A. H.; Wardani, D. K.; Aini, F. N.; Sari, P. L.; Tamtama, B. P. N.; Kristiawan, Y. R.

2017-04-01

Recently, the uses of dyes are increasingly widespread especially in foods and beverages as food colors to attract the consumers. The dye that currently attracts is indigo. Indigo is a group of carbonyl compounds, one of the oldest known dyes in terms of natural blue dye derived from the Indigofera tinctoria plant. The use of indigo as a natural food dye intended to reduce the use of synthetic dyes are carcinogenic impact. The method used in this study includes the analysis of indigo using UV-Vis spectrophotometry and FTIR analysis. Based on the UV-Vis Spectrophotometer analysis results with the various concentrations of 0.002 mg/mL; 0.004 mg/mL; 0.006 mg/mL and 0.008 mg/mL were obtained maximum absorption peak at wavelength of 550-700 nm. The indigo dyes in various concentrations produce a stable pH at an average pH 9, therefore it can make the colors not easily fade (strong staining). Based on infrared spectrophotometer measurement were obtained absorption spectrum at 3100-3500 cm-1 as primary N-H and secondary amine, 1600 cm-1 as aromatic C=C, 1000-1350 cm-1 as aromatic C-N, 690-900 cm-1 as aromatic C-H.

Antimicrobial activity of Olea europaea Linné extracts and their applicability as natural food preservative agents.

PubMed

Thielmann, J; Kohnen, S; Hauser, C

2017-06-19

The antimicrobial activity of phenolic compounds from Olea (O.) europaea Linné (L.) is part of the scientific discussion regarding the use of natural plant extracts as alternative food preservative agents. Although, the basic knowledge on the antimicrobial potential of certain molecules such as oleuropein, hydroxytyrosol or elenolic acid derivatives is given, there is still little information regarding their applicability for food preservation. This might be primarily due to the lack of information regarding the full antimicrobial spectrum of the compounds, their synergisms in natural or artificial combinations and their interaction with food ingredients. The present review accumulates available literature from the past 40 years, investigating the antimicrobial activity of O. europaea L. derived extracts and compounds in vitro and in food matrices, in order to evaluate their food applicability. In summary, defined extracts from olive fruit or leaves, containing the strongest antimicrobial compounds hydroxytyrosol, oleacein or oleacanthal in considerable concentrations, appear to be suitable for food preservation. Nonetheless there is still need for consequent research on the compounds activity in food matrices, their effect on the natural microbiota of certain foods and their influence on the sensorial properties of the targeted products. Copyright © 2017 Elsevier B.V. All rights reserved.

Early emerging system for reasoning about the social nature of food.

PubMed

Liberman, Zoe; Woodward, Amanda L; Sullivan, Kathleen R; Kinzler, Katherine D

2016-08-23

Selecting appropriate foods is a complex and evolutionarily ancient problem, yet past studies have revealed little evidence of adaptations present in infancy that support sophisticated reasoning about perceptual properties of food. We propose that humans have an early-emerging system for reasoning about the social nature of food selection. Specifically, infants' reasoning about food choice is tied to their thinking about agents' intentions and social relationships. Whereas infants do not expect people to like the same objects, infants view food preferences as meaningfully shared across individuals. Infants' reasoning about food preferences is fundamentally social: They generalize food preferences across individuals who affiliate, or who speak a common language, but not across individuals who socially disengage or who speak different languages. Importantly, infants' reasoning about food preferences is flexibly calibrated to their own experiences: Tests of bilingual babies reveal that an infant's sociolinguistic background influences whether she will constrain her generalization of food preferences to people who speak the same language. Additionally, infants' systems for reasoning about food is differentially responsive to positive and negative information. Infants generalize information about food disgust across all people, regardless of those people's social identities. Thus, whereas food preferences are seen as embedded within social groups, disgust is interpreted as socially universal, which could help infants avoid potentially dangerous foods. These studies reveal an early-emerging system for thinking about food that incorporates social reasoning about agents and their relationships, and allows infants to make abstract, flexible, adaptive inferences to interpret others' food choices.

Early emerging system for reasoning about the social nature of food

PubMed Central

Liberman, Zoe; Woodward, Amanda L.; Sullivan, Kathleen R.; Kinzler, Katherine D.

2016-01-01

Selecting appropriate foods is a complex and evolutionarily ancient problem, yet past studies have revealed little evidence of adaptations present in infancy that support sophisticated reasoning about perceptual properties of food. We propose that humans have an early-emerging system for reasoning about the social nature of food selection. Specifically, infants’ reasoning about food choice is tied to their thinking about agents’ intentions and social relationships. Whereas infants do not expect people to like the same objects, infants view food preferences as meaningfully shared across individuals. Infants’ reasoning about food preferences is fundamentally social: They generalize food preferences across individuals who affiliate, or who speak a common language, but not across individuals who socially disengage or who speak different languages. Importantly, infants’ reasoning about food preferences is flexibly calibrated to their own experiences: Tests of bilingual babies reveal that an infant’s sociolinguistic background influences whether she will constrain her generalization of food preferences to people who speak the same language. Additionally, infants’ systems for reasoning about food is differentially responsive to positive and negative information. Infants generalize information about food disgust across all people, regardless of those people’s social identities. Thus, whereas food preferences are seen as embedded within social groups, disgust is interpreted as socially universal, which could help infants avoid potentially dangerous foods. These studies reveal an early-emerging system for thinking about food that incorporates social reasoning about agents and their relationships, and allows infants to make abstract, flexible, adaptive inferences to interpret others’ food choices. PMID:27503878

Methods for the determination of European Union-permitted added natural colours in foods: a review.

PubMed

Scotter, M J

2011-05-01

Coupled to increasing consumer demand, food manufacturers have moved towards increased usage of approved natural colours. There is a legal requirement for governments to monitor the consumption of all food additives in the European Union to ensure the acceptable daily intakes (ADIs) are not exceeded, especially by young children. Validated analytical methods are needed to fulfil this requirement. The aim of this paper is to review the available literature on methods of extraction for approved natural colours in food and drink. Available analytical methods for the determination of European Union-permitted natural food colour additives in foods and beverages have been assessed for their fitness for purpose in terms of their key extraction and analysis procedures, selectivity and sensitivity, especially with regard to maximum permitted levels, and their applicability for use in surveillance and in an enforcement role. The advantages and disadvantages of available analytical methods for each of nine designated chemical classes (groups) of natural colours in different food and beverage matrices are given. Other important factors such as technical requirements, cost, transferability and applicability are given due consideration. Gaps in the knowledge and levels of validation are identified and recommendations made on further research to develop suitable methods. The nine designated natural colour classes covered are: 1. Curcumin (E100), 2. Riboflavins (E101i-ii), 3. Cochineal (E120), 4. Chlorophylls--including chlorophyllins and copper analogues (E140-141), 5. Caramel Classes I-IV (E150a-d), 6. Carotenoids (E160a-f, E161b, E161g), 7. Beetroot red (E162), 8. Anthocyanins (E163), and 9. Other colours--Vegetable carbon (E153), Calcium carbonate (E170), Titanium dioxide (E171) and Iron oxides and hydroxides (E172).

Cooking methods employing natural anti-oxidant food additives effectively reduced concentration of nephrotoxic and carcinogenic aristolochic acids in contaminated food grains.

PubMed

Li, Weiwei; Chan, Chi-Kong; Wong, Yee-Lam; Chan, K K Jason; Chan, Ho Wai; Chan, Wan

2018-10-30

Emerging evidence suggests that aristolochic acids (AA) produced naturally by a common weed Aristolochia clematitis in the cultivation fields is contaminating the food products in Balkan Peninsula and acting as the etiological agent in the development of Balkan endemic nephropathy. In this study, we investigated the combined use of natural anti-oxidative "food additives" and different cooking methods to find a solution for the widespread contamination of AA in food products. The results indicated that the addition of healthy dietary supplements (such as cysteine, glutathione, ascorbic acid, citric acid and magnesium) during cooking, is a highly efficient method in lowering the concentration of AA in the final food products. Because previous observation indicated one of the toxicological mechanisms by which AA exert its toxicity is to induce oxidative stress in internal organs, it is anticipated that these added anti-oxidants will also help to attenuate the nephrotoxicity of AA. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structural and evolutionary relationships of "AT-less" type I polyketide synthase ketosynthases.

PubMed

Lohman, Jeremy R; Ma, Ming; Osipiuk, Jerzy; Nocek, Boguslaw; Kim, Youngchang; Chang, Changsoo; Cuff, Marianne; Mack, Jamey; Bigelow, Lance; Li, Hui; Endres, Michael; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N; Shen, Ben

2015-10-13

Acyltransferase (AT)-less type I polyketide synthases (PKSs) break the type I PKS paradigm. They lack the integrated AT domains within their modules and instead use a discrete AT that acts in trans, whereas a type I PKS module minimally contains AT, acyl carrier protein (ACP), and ketosynthase (KS) domains. Structures of canonical type I PKS KS-AT didomains reveal structured linkers that connect the two domains. AT-less type I PKS KSs have remnants of these linkers, which have been hypothesized to be AT docking domains. Natural products produced by AT-less type I PKSs are very complex because of an increased representation of unique modifying domains. AT-less type I PKS KSs possess substrate specificity and fall into phylogenetic clades that correlate with their substrates, whereas canonical type I PKS KSs are monophyletic. We have solved crystal structures of seven AT-less type I PKS KS domains that represent various sequence clusters, revealing insight into the large structural and subtle amino acid residue differences that lead to unique active site topologies and substrate specificities. One set of structures represents a larger group of KS domains from both canonical and AT-less type I PKSs that accept amino acid-containing substrates. One structure has a partial AT-domain, revealing the structural consequences of a type I PKS KS evolving into an AT-less type I PKS KS. These structures highlight the structural diversity within the AT-less type I PKS KS family, and most important, provide a unique opportunity to study the molecular evolution of substrate specificity within the type I PKSs.

Ruthenium-catalyzed insertion of adjacent diol carbon atoms into C-C bonds: Entry to type II polyketides.

PubMed

Bender, Matthias; Turnbull, Ben W H; Ambler, Brett R; Krische, Michael J

2017-08-25

Current catalytic processes involving carbon-carbon bond activation rely on π-unsaturated coupling partners. Exploiting the concept of transfer hydrogenative coupling, we report a ruthenium(0)-catalyzed cycloaddition of benzocyclobutenones that functionalizes two adjacent saturated diol carbon-hydrogen bonds. These regio- and diastereoselective processes enable convergent construction of type II polyketide substructures. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

The Conformational Flexibility of the Acyltransferase from the Disorazole Polyketide Synthase Is Revealed by an X-ray Free-Electron Laser Using a Room-Temperature Sample Delivery Method for Serial Crystallography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathews, Irimpan I.; Allison, Kim; Robbins, Thomas

The crystal structure of the trans-acyltransferase (AT) from the disorazole polyketide synthase (PKS) was determined at room temperature to a resolution of 2.5 Å using a new method for sample delivery directly into an X-ray free-electron laser. A novel sample extractor efficiently delivered limited quantities of microcrystals directly from the native crystallization solution into the X-ray beam at room temperature. The AT structure revealed important catalytic features of this core PKS enzyme, including the occurrence of conformational changes around the active site. The implications of these conformational changes on polyketide synthase reaction dynamics are discussed.

The Conformational Flexibility of the Acyltransferase from the Disorazole Polyketide Synthase Is Revealed by an X-ray Free-Electron Laser Using a Room-Temperature Sample Delivery Method for Serial Crystallography

DOE PAGES

Mathews, Irimpan I.; Allison, Kim; Robbins, Thomas; ...

2017-08-23

The crystal structure of the trans-acyltransferase (AT) from the disorazole polyketide synthase (PKS) was determined at room temperature to a resolution of 2.5 Å using a new method for sample delivery directly into an X-ray free-electron laser. A novel sample extractor efficiently delivered limited quantities of microcrystals directly from the native crystallization solution into the X-ray beam at room temperature. The AT structure revealed important catalytic features of this core PKS enzyme, including the occurrence of conformational changes around the active site. The implications of these conformational changes on polyketide synthase reaction dynamics are discussed.

Phylogenetic diversity of culturable endophytic fungi in Dongxiang wild rice (Oryza rufipogon Griff), detection of polyketide synthase gene and their antagonistic activity analysis.

PubMed

Wang, Ya; Gao, Bo Liang; Li, Xi Xi; Zhang, Zhi Bin; Yan, Ri Ming; Yang, Hui Lin; Zhu, Du

2015-11-01

The biodiversity of plant endophytic fungi is enormous, numerous competent endophytic fungi are capable of providing different forms of fitness benefits to host plants and also could produce a wide array of bioactive natural products, which make them a largely unexplored source of novel compounds with potential bioactivity. In this study, we provided a first insights into revealing the diversity of culturable endophytic fungi in Dongxiang wild rice (Oryza rufipogon Griff.) from China using rDNA-ITS phylogenetic analysis. Here, the potential of fungi in producing bioactive natural products was estimated based on the beta-ketosynthase detected in the polyketide synthase (PKS) gene cluster and on the bioassay of antagonistic activity against two rice phytopathogens Thanatephorus cucumeris and Xanthomonas oryzae. A total of 229 endophytic fungal strains were validated in 19 genera. Among the 24 representative strains, 13 strains displayedantagonistic activity against the phytopathogens. Furthermore, PKS genes were detected in 9 strains, indicating their potential for synthesising PKS compounds. Our study confirms the phylogenetic diversity of endophytic fungi in O. rufipogon G. and highlights that endophytic fungi are not only promising resources of biocontrol agents against phytopathogens of rice plants, but also of bioactive natural products and defensive secondary metabolites. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Direct Capture and Heterologous Expression of Salinispora Natural Product Genes for the Biosynthesis of Enterocin

PubMed Central

2015-01-01

Heterologous expression of secondary metabolic pathways is a promising approach for the discovery and characterization of bioactive natural products. Herein we report the first heterologous expression of a natural product from the model marine actinomycete genus Salinispora. Using the recently developed method of yeast-mediated transformation-associated recombination for natural product gene clusters, we captured a type II polyketide synthase pathway from Salinispora pacifica with high homology to the enterocin pathway from Streptomyces maritimus and successfully produced enterocin in two different Streptomyces host strains. This result paves the way for the systematic interrogation of Salinispora’s promising secondary metabolome. PMID:25382643

Direct capture and heterologous expression of Salinispora natural product genes for the biosynthesis of enterocin.

PubMed

Bonet, Bailey; Teufel, Robin; Crüsemann, Max; Ziemert, Nadine; Moore, Bradley S

2015-03-27

Heterologous expression of secondary metabolic pathways is a promising approach for the discovery and characterization of bioactive natural products. Herein we report the first heterologous expression of a natural product from the model marine actinomycete genus Salinispora. Using the recently developed method of yeast-mediated transformation-associated recombination for natural product gene clusters, we captured a type II polyketide synthase pathway from Salinispora pacifica with high homology to the enterocin pathway from Streptomyces maritimus and successfully produced enterocin in two different Streptomyces host strains. This result paves the way for the systematic interrogation of Salinispora's promising secondary metabolome.

iso-Migrastatin, migrastatin, and dorrigocin production in Streptomyces platensis NRRL 18993 is governed by a single biosynthetic machinery featuring an acyltransferase-less type I polyketide synthase.

PubMed

Lim, Si-Kyu; Ju, Jianhua; Zazopoulos, Emmanuel; Jiang, Hui; Seo, Jeong-Woo; Chen, Yihua; Feng, Zhiyang; Rajski, Scott R; Farnet, Chris M; Shen, Ben

2009-10-23

iso-Migrastatin and related glutarimide-containing polyketides are potent inhibitors of tumor cell migration and their implied potential as antimetastatic agents for human cancers has garnered significant attention. Genome scanning of Streptomyces platensis NRRL 18993 unveiled two candidate gene clusters (088D and mgs); each encodes acyltransferase-less type I polyketide synthases commensurate with iso-migrastatin biosynthesis. Both clusters were inactivated by lambda-RED-mediated PCR-targeting mutagenesis in S. platensis; iso-migrastatin production was completely abolished in the DeltamgsF mutant SB11012 strain, whereas inactivation of 088D-orf7 yielded the SB11006 strain that exhibited no discernible change in iso-migrastatin biosynthesis. These data indicate that iso-migrastatin production is governed by the mgs cluster. Systematic gene inactivation allowed determination of the precise boundaries of the mgs cluster and the essentiality of the genes within the mgs cluster in iso-migrastatin production. The mgs cluster consists of 11 open reading frames that encode three acyltransferase-less type I polyketide synthases (MgsEFG), one discrete acyltransferase (MgsH), a type II thioesterase (MgsB), three post-PKS tailoring enzymes (MgsIJK), two glutarimide biosynthesis enzymes (MgsCD), and one regulatory protein (MgsA). A model for iso-migrastatin biosynthesis is proposed based on functional assignments derived from bioinformatics and is further supported by the results of in vivo gene inactivation experiments.

iso-Migrastatin, Migrastatin, and Dorrigocin Production in Streptomyces platensis NRRL 18993 Is Governed by a Single Biosynthetic Machinery Featuring an Acyltransferase-less Type I Polyketide Synthase*

PubMed Central

Lim, Si-Kyu; Ju, Jianhua; Zazopoulos, Emmanuel; Jiang, Hui; Seo, Jeong-Woo; Chen, Yihua; Feng, Zhiyang; Rajski, Scott R.; Farnet, Chris M.; Shen, Ben

2009-01-01

iso-Migrastatin and related glutarimide-containing polyketides are potent inhibitors of tumor cell migration and their implied potential as antimetastatic agents for human cancers has garnered significant attention. Genome scanning of Streptomyces platensis NRRL 18993 unveiled two candidate gene clusters (088D and mgs); each encodes acyltransferase-less type I polyketide synthases commensurate with iso-migrastatin biosynthesis. Both clusters were inactivated by λ-RED-mediated PCR-targeting mutagenesis in S. platensis; iso-migrastatin production was completely abolished in the ΔmgsF mutant SB11012 strain, whereas inactivation of 088D-orf7 yielded the SB11006 strain that exhibited no discernible change in iso-migrastatin biosynthesis. These data indicate that iso-migrastatin production is governed by the mgs cluster. Systematic gene inactivation allowed determination of the precise boundaries of the mgs cluster and the essentiality of the genes within the mgs cluster in iso-migrastatin production. The mgs cluster consists of 11 open reading frames that encode three acyltransferase-less type I polyketide synthases (MgsEFG), one discrete acyltransferase (MgsH), a type II thioesterase (MgsB), three post-PKS tailoring enzymes (MgsIJK), two glutarimide biosynthesis enzymes (MgsCD), and one regulatory protein (MgsA). A model for iso-migrastatin biosynthesis is proposed based on functional assignments derived from bioinformatics and is further supported by the results of in vivo gene inactivation experiments. PMID:19726666

Six New Polyketide Decalin Compounds from Mangrove Endophytic Fungus Penicillium aurantiogriseum 328#

PubMed Central

Ma, Yanhong; Li, Jing; Huang, Meixiang; Liu, Lan; Wang, Jun; Lin, Yongcheng

2015-01-01

Six new compounds with polyketide decalin ring, peaurantiogriseols A–F (1–6), along with two known compounds, aspermytin A (7), 1-propanone,3-hydroxy-1-(1,2,4a,5,6,7,8,8a-octahydro-2,5-dihydroxy-1,2,6-trimethyl-1-naphthalenyl) (8), were isolated from the fermentation products of mangrove endophytic fungus Penicillium aurantiogriseum 328#. Their structures were elucidated based on their structure analysis. The absolute configurations of compounds 1 and 2 were determined by 1H NMR analysis of their Mosher esters; the absolute configurations of 3–6 were determined by using theoretical calculations of electronic circular dichroism (ECD). Compounds 1–8 showed low inhibitory activity against human aldose reductase, no activity of inducing neurite outgrowth, nor antimicrobial activity. PMID:26473887

Best practices for using natural experiments to evaluate retail food and beverage policies and interventions.

PubMed

Taillie, Lindsey Smith; Grummon, Anna H; Fleischhacker, Sheila; Grigsby-Toussaint, Diana S; Leone, Lucia; Caspi, Caitlin Eicher

2017-12-01

Policy and programmatic change in the food retail setting, including excise taxes on beverages with added-caloric sweeteners, new supermarkets in food deserts, and voluntary corporate pledges, often require the use of natural experimental evaluation for impact evaluation when randomized controlled trials are not possible. Although natural experimental studies in the food retail setting provide important opportunities to test how nonrandomized interventions affect behavioral and health outcomes, researchers face several key challenges to maintaining strong internal and external validity when conducting these studies. Broadly, these challenges include 1) study design and analysis; 2) selection of participants, selection of measures, and obtainment of data; and 3) real-world considerations. This article addresses these challenges and different approaches to meeting them. Case studies are used to illustrate these approaches and to highlight advantages and disadvantages of each approach. If the trade-offs required to address these challenges are carefully considered, thoughtful natural experimental evaluations can minimize bias and provide critical information about the impacts of food retail interventions to a variety of stakeholders, including the affected population, policymakers, and food retailers. © The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Identification of natural lactoylcholine in lactic acid bacteria-fermented food.

PubMed

Nakamura, Kozo; Okitsu, Sho; Ishida, Ryuya; Tian, Su; Igari, Naoki; Amano, Yoshihiko

2016-06-15

Acetylcholine (AcCh) is a major neurotransmitter and an agonist of nicotinic and muscarinic receptors in non-neuronal systems. Artificially synthesized lactoylcholine (LaCh) has potent nicotinic activity equal to that of AcCh. In this study, we report the isolation and purification of natural AcCh and LaCh from a lactic-fermented food known to reduce blood pressure. To our knowledge, we are the first to isolate natural LaCh. The choline esters were isolated using a novel purification procedure combining a weak cation-exchange cartridge with ODS and pentafluorophenyl HPLC columns, and the structure of LaCh was identified via various analyses. Assessment of D- and L-LaCh showed that the isolated LaCh was an enantiomer mixture with a D/L ratio of 1.6. D-LaCh induced vasorelaxation of thoracic aortas from spontaneously hypertensive rats (EC50=3.83×10(-7) M), while L-LaCh did not. Our results suggest that choline esters could be new functional ingredients in lactic-fermented foods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Getting More Than You Paid For: Unauthorized "Natural" Substances in Herbal Food Supplements on EU Market.

PubMed

Zovko Končić, Marijana

2018-04-01

As the population in the industrialized world develops preference for what is perceived as a natural and holistic way of disease treatment, the popularity and the number of food supplements on the market, including herbal ones, is experiencing an unprecedented rise. However, unlike herbal medicinal products, intended for treating or preventing disease, current legislation classifies food supplements as products intended for achieving nutritional or physiological effect and to supplement the normal diet. Accordingly, most food supplements are not to be associated with specific health claims. However, either due to the subtle suggestions by the producers or the wishful thinking of the consumers, certain pharmacological effects from food supplements are often expected. Medicinal plants included in food supplements usually do not produce dramatic and instant pharmacological effects. Therefore, in order to meet the expectation of their customers, some producers have turned to the illicit and dangerous practice of adulterating their products with synthetic adulterants, including naturally occurring molecules, having the desired activity. Such practice is prevalent in, although not limited to, food supplements intended for use as weight-loss aids, as well as for sport performance and libido enhancement. The review is focusing on naturally occurring alkaloids, phenylethanolamines, and their semi-synthetic derivatives in food supplements in the European Union as reported by the Rapid Alert System for Food and Feed. Their desired and undesired pharmacological effects, as well as the methods for their detection and quantification in food supplements, will be reviewed. Georg Thieme Verlag KG Stuttgart · New York.

Food Security and Women's Access to Natural Resources workshop; a brief report.

PubMed

1997-01-01

This article describes the workshop on Food Security and Women's Access to Natural Resources, held in January 1997 in Mumbai, India. The workshop was organized jointly by the Tata Institute of Social Sciences and the Indian Association of Women's Studies. The aim was to examine the food security situation in Maharashtra and Gujarat states in the west, the initiative to build alternative institutions, legal changes augmenting industrialization, and how traditional rights to common property resources can be legalized and how the poor can have access to new resources. The workshop organizers were unable to obtain experts on some topics. Core discussion centered on changes in industrialization, natural resources, gender and food security; access to natural resources and poverty alleviation programs; initiatives to create food security; and laws related to access to land and water. Discussions revealed the alienation of small and marginal farmers, landless laborers, and artisans from their livelihoods and survival strategies for these disenfranchised groups. The design of drought eradication and water conservation programs did not permit women and men working at construction sites to have access to the program assets. Case studies revealed situations in which women won the right of access to community water and then negotiated for land in lease. The women used landowners to negotiate credit and access development program assets, but normal channels of the National Bank of Agricultural Research and Development could have provided these benefits. Participants discussed how governments can be held accountable and how public funds could be used to revamp poverty alleviation and asset creation programs. All agreed that macrolevel development should give priority to agricultural development and legal constraints or problems. Five follow-up activities are identified.

Food supply chain disruption due to natural disaster: Entities, risks and strategies for resilience

USDA-ARS?s Scientific Manuscript database

The resilience of food supply chain (FSC) to disruptions has not kept pace with the extended, globalized and complex network of modern food chain. This chapter presents a holistic view of the FSC, interactions among its components, risks and vulnerabilities of disruption in the context of natural d...

The Conformational Flexibility of the Acyltransferase from the Disorazole Polyketide Synthase Is Revealed by an X-ray Free-Electron Laser Using a Room-Temperature Sample Delivery Method for Serial Crystallography

PubMed Central

Allison, Kim; Robbins, Thomas; Lyubimov, Artem Y.; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Khosla, Chaitan; DeMirci, Hasan; McPhillips, Scott E.; Hollenbeck, Michael; Soltis, Michael; Cohen, Aina E.

2017-01-01

The crystal structure of the trans-acyltrans-ferase (AT) from the disorazole polyketide synthase (PKS) was determined at room temperature to a resolution of 2.5 Å using a new method for the direct delivery of the sample into an X-ray free-electron laser. A novel sample extractor efficiently delivered limited quantities of microcrystals directly from the native crystallization solution into the X-ray beam at room temperature. The AT structure revealed important catalytic features of this core PKS enzyme, including the occurrence of conformational changes around the active site. The implications of these conformational changes for polyketide synthase reaction dynamics are discussed. PMID:28832129

Functional Reconstitution of a Fungal Natural Product Gene Cluster by Advanced Genome Editing.

PubMed

Weber, Jakob; Valiante, Vito; Nødvig, Christina S; Mattern, Derek J; Slotkowski, Rebecca A; Mortensen, Uffe H; Brakhage, Axel A

2017-01-20

Filamentous fungi produce varieties of natural products even in a strain dependent manner. However, the genetic basis of chemical speciation between strains is still widely unknown. One example is trypacidin, a natural product of the opportunistic human pathogen Aspergillus fumigatus, which is not produced among different isolates. Combining computational analysis with targeted gene editing, we could link a single nucleotide insertion in the polyketide synthase of the trypacidin biosynthetic pathway and reconstitute its production in a nonproducing strain. Thus, we present a CRISPR/Cas9-based tool for advanced molecular genetic studies in filamentous fungi, exploiting selectable markers separated from the edited locus.

Television food advertising in Singapore: the nature and extent of children's exposure.

PubMed

Huang, Liyan; Mehta, Kaye; Wong, Mun Loke

2012-06-01

Television advertising is an effective medium for reaching young children and influencing their food choice. Studies have shown that messages conveyed by food advertisements are rarely consistent with healthy eating messages. With the increasing purchasing power of children, food companies are focusing on children as lucrative target audiences. Extensive marketing of energy-dense, nutrient-poor foods to children potentially contributes to the 'obesogenic' environment. This study aims to determine the degree and nature of food advertisements that Singaporean children are exposed to on television. Ninety-eight hours of children's television programmes broadcast by free-to-air stations were recorded and analysed. Advertisements with the intent of selling and sponsorships for programmes were included. Foods advertised were considered healthy if they met the criteria of the Healthier Choice Symbol in Singapore. Of the 1344 advertisements and sponsorships identified, 33% were for food. Of the food advertisements, 38% were considered healthy, while 57% were not. Candy, confectionery and fast food advertisements accounted for 46% of total food advertisements. Significantly more unhealthy food advertisements were screened on weekends compared with weekdays (p < 0.001). This is the first content analysis of television advertisements in Singapore and the results of this study provide background data on the extent of food advertising that children in Singapore are exposed to. Consistent with other countries, unhealthy food advertisements continue to dominate children's television programmes. This study suggests that Singaporean children are exposed to high levels of advertising for unhealthy foods. The study provides a baseline against which measures aimed at reducing children's exposure to television food advertising can be evaluated.

The role of food-security solutions in the protection of natural resources and environment of developing countries.

PubMed

Lashgarara, Farhad; Mirdamadi, Seyyed Mehdi; Hosseini, Seyyed Jamal Farajollah; Chizari, Mohammad

2008-10-01

The majority of the countries of the world, especially developing countries, face environmental problems. Limitations of basic resources (water and soil) and population growth have been the cause of these environmental problems that countries are confronted with. Developing countries have numerous problems, including destruction of forests, vegetable and animal species, and pollution of the environment. Damage to natural resources and the environment can influence the food-security situation. One of the main millennium development goals (MDGs) is protection of the environment and people's health. This cannot obtained unless there is ensured food security. Food security has been defined as a situation when all people, at all times, have physical and economic access to sufficient, safe, and nutritious food needed to maintain a healthy and active life. At the same time, with ensured food security, we can hope to protect the natural resources and environment. The methodology used is descriptive-analytical, and its main purpose is determining the importance and role of food-security solutions in the reduction of environmental hazards and improvement of natural resources and the environmental situation in developing countries. Therefore, some of the most important food-security solutions that can play an important role in this relation were discussed, including conventional research-based technology, biotechnology, information and communication technologies (ICTs), alternative energy sources, and food irradiation.

Structural and evolutionary relationships of "AT-less" type I polyketide synthase ketosynthases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lohman, Jeremy; Ma, Ming; Osipiuk, Jerzy

2015-10-13

Acyltransferase (AT)-less type I polyketide synthases (PKSs) break the type I PKS paradigm. They lack the integrated AT domains within their modules and instead use a discrete AT that acts in trans, whereas a type I PKS module minimally contains AT, acyl carrier protein (ACP), and ketosynthase (KS) domains. Structures of canonical type I PKS KS-AT didomains reveal structured linkers that connect the two domains. AT-less type I PKS KSs have remnants of these linkers, which have been hypothesized to be AT docking domains. Natural products produced by AT-less type I PKSs are very complex because of an increased representationmore » of unique modifying domains. AT-less type I PKS KSs possess substrate specificity and fall into phylogenetic clades that correlate with their substrates, whereas canonical type I PKS KSs are monophyletic. We have solved crystal structures of seven AT-less type I PKS KS domains that represent various sequence clusters, revealing insight into the large structural and subtle amino acid residue differences that lead to unique active site topologies and substrate specificities. One set of structures represents a larger group of KS domains from both canonical and AT-less type I PKSs that accept amino acid-containing substrates. One structure has a partial AT-domain, revealing the structural consequences of a type I PKS KS evolving into an AT-less type I PKS KS. These structures highlight the structural diversity within the AT-less type I PKS KS family, and most important, provide a unique opportunity to study the molecular evolution of substrate specificity within the type I PKSs.« less

The synergism of natural compounds in the pursuit of safe and healthier food.

PubMed

Szczepaniak, S; Polanska, M; Van Assche, A; Moloney, R; Willems, K A

2011-01-01

Food producers apply modern processing techniques and use a variety of preservative additives to guarantee safe food and a longer shelflife. Regrettably many of these impact the sensory characteristics of the foodstuffs, such as colour, texture, and flavour, which can result in low consumer acceptance. Additionally, strategies used to reduce growth of spoilage and pathogenic bacteria are not selective enough and may inactivate also desired microbiota. Food is usually overdosed with antimicrobials that are supplemented 'just in case.' Consequently, food producers are searching for natural preservation methods that are not harmful to humans. Nature offers a wide spectrum of biologically active (phyto) chemicals that can be used as potential natural preservatives. Compounds with bacterial growth-limiting properties are detected in all parts of plants, including their leaves, flowers, fruits, roots, etc. These are mostly acids, alcohols, medium and long-chain organic acids, terpenic compounds, and their derivatives. This study focused on the effectiveness of plant extracts, i.e., synergism between terpenoids and medium chain fatty acids in cured cooked meat. Bacterial strains that were tested include typical members of the spoilage microflora in vacuum (Lactobacillus curvatus) and MA-packed meats (Brochothrix thermosphacta). These were isolated and identified in a separate study. L. curvatus was observed to be very resistant against either terpenoids or fatty acids when used separately, whereas its growth was strongly inhibited when both chemicals were combined. Growth of B. thermosphacta was significantly inhibited when antimicrobial compounds were solely applied, whereas a blend of terpenoids and fatty acids showed an almost bactericidal effect.

Could 1,3 dimethylamylamine (DMAA) in food supplements have a natural origin?

PubMed

Di Lorenzo, Chiara; Moro, Enzo; Dos Santos, Ariana; Uberti, Francesca; Restani, Patrizia

2013-02-01

1,3 dimethylamylamine or methylexaneamine (DMAA) is a synthetic pharmaceutical patented in the 1940s as a nasal decongestant which can be used as a recreational stimulant. Alleged to occur in nature, DMAA has become a widely used ingredient in sports food supplements, despite its status as a doping agent and concerns over its safety. There is now some doubt as to whether it can be sourced naturally or whether it actually occurs naturally at all. The presence of DMAA was investigated by high performance liquid chromatography (HPLC) in extracts of the leaves and stems of four geranium species and of three well-known cultivars. The amounts of DMAA in commercial geranium (Pelargonium graveolens) oil and the leading sports supplement which uses the ingredient were also measured. DMAA was not found in any of the leaves or stems or in the commercial geranium oil included in this study. Approximately 30 mg per daily dose was found in the food supplement. Therefore, the amount of DMAA found in the supplement is most unlikely to have been sourced in nature, and it must be concluded that synthetic DMAA, known to be capable of causing severe adverse physiological effects, has been added. Copyright © 2012 John Wiley & Sons, Ltd.

The Post-polyketide Synthase Steps in iso-Migrastatin Biosynthesis Featuring Tailoring Enzymes with Broad Substrate Specificity

PubMed Central

Ma, Ming; Kwong, Thomas; Lim, Si-Kyu; Ju, Jianhua; Lohman, Jeremy R.; Shen, Ben

2013-01-01

The iso-migrastatin (iso-MGS) biosynthetic gene cluster from Streptomyces platensis NRRL 18993 consists of 11 genes, featuring an acyltransferase (AT)-less type I polyketide synthase (PKS) and three tailoring enzymes MgsIJK. Systematic inactivation of mgsIJK in S. platensis enabled us to (i) identify two nascent products (10 and 13) of the iso-MGS AT-less type I PKS, establishing an unprecedented novel feature for AT-less type I PKSs, and (ii) account for the formation of all known post-PKS biosynthetic intermediates (10-17) generated by the three tailoring enzymes MgsIJK, which possessed significant substrate promiscuities. PMID:23394593

Thermostable phycocyanin from the red microalga Cyanidioschyzon merolae, a new natural blue food colorant.

PubMed

Rahman, D Y; Sarian, F D; van Wijk, A; Martinez-Garcia, M; van der Maarel, M J E C

2017-01-01

The demand for natural food colorants is growing as consumers question the use of artificial colorants more and more. The phycobiliprotein C-phycocyanin of Arthospira platensis is used as a natural blue colorant in certain food products. The thermoacidophilic red microalga Cyanidioschyzon merolae might provide an alternative source of phycocyanin. Cyanidioschyzon merolae belongs to the order Cyanidiophyceae of the phylum Rhodophyta. Its natural habitat are sulfuric hot springs and geysers found near volcanic areas in, e.g., Yellowstone National Park in the USA and in Java, Indonesia. It grows optimally at a pH between 0.5 and 3.0 and at temperatures up to 56 °C. The low pH at which C . merolae grows minimizes the risk of microbial contamination and could limit production loss. As C . merolae lacks a cell wall, phycocyanin with a high purity number of 9.9 could be extracted by an osmotic shock using a simple ultrapure water extraction followed by centrifugation. The denaturation midpoint at pH 5 was 83 °C, being considerably higher than the A . platensis phycocyanin (65 °C). The C . merolae phycocyanin was relatively stable at pH 4 and 5 up to 80 °C. The high thermostability at slightly acidic pH makes the C . merolae phycocyanin an interesting alternative to A . platensis phycocyanin as a natural blue food colorant.

Chemoenzymatic Total Synthesis and Structural Diversification of Tylactone-Based Macrolide Antibiotics through Late-Stage Polyketide Assembly, Tailoring, and C-H Functionalization.

PubMed

Lowell, Andrew N; DeMars, Matthew D; Slocum, Samuel T; Yu, Fengan; Anand, Krithika; Chemler, Joseph A; Korakavi, Nisha; Priessnitz, Jennifer K; Park, Sung Ryeol; Koch, Aaron A; Schultz, Pamela J; Sherman, David H

2017-06-14

Polyketide synthases (PKSs) represent a powerful catalytic platform capable of effecting multiple carbon-carbon bond forming reactions and oxidation state adjustments. We explored the functionality of two terminal PKS modules that produce the 16-membered tylosin macrocycle, using them as biocatalysts in the chemoenzymatic synthesis of tylactone and its subsequent elaboration to complete the first total synthesis of the juvenimicin, M-4365, and rosamicin classes of macrolide antibiotics via late-stage diversification. Synthetic chemistry was employed to generate the tylactone hexaketide chain elongation intermediate that was accepted by the juvenimicin (Juv) ketosynthase of the penultimate JuvEIV PKS module. The hexaketide is processed through two complete modules (JuvEIV and JuvEV) in vitro, which catalyze elongation and functionalization of two ketide units followed by cyclization of the resulting octaketide into tylactone. After macrolactonization, a combination of in vivo glycosylation, selective in vitro cytochrome P450-mediated oxidation, and chemical oxidation was used to complete the scalable construction of a series of macrolide natural products in as few as 15 linear steps (21 total) with an overall yield of 4.6%.

Fast or slow-foods? Describing natural variations in oral processing characteristics across a wide range of Asian foods.

PubMed

Forde, C G; Leong, C; Chia-Ming, E; McCrickerd, K

2017-02-22

The structural properties of foods have a functional role to play in oral processing behaviours and sensory perception, and also impact on meal size and the experience of fullness. This study adopted a new approach by using behavioural coding analysis of eating behaviours to explore how a range of food textures manifest as the microstructural properties of eating and expectations of fullness. A selection of 47 Asian foods were served in fixed quantities to a panel of participants (N = 12) and their eating behaviours were captured via web-camera recordings. Behavioural coding analysis was completed on the recordings to extract total bites, chews and swallows and cumulative time of the food spent in the mouth. From these measurements a series of microstructural properties including average bite size (g), chews per bite, oro-sensory exposure time (seconds) and average eating rate (g min -1 ) were derived per food. The sensory and macronutrient properties of each food were correlated with the microstructure of eating to compare the differences in eating behaviour on a gram for gram basis. There were strong relationships between the perceived food textural properties and its eating behaviours and a food's total water content was the best predictor of its eating rate. Foods that were eaten at a slower eating rate, with smaller bites and more chews per bite were rated as higher in the expected fullness. These relationships are important as oral processing behaviours and beliefs about the potential satiating value of food influence portion decisions and moderate meal size. These data support the idea that naturally occurring differences in the food structure and texture could be used to design meals that slow the rate of eating and maximise fullness.

Application of the BRAFO-tiered approach for benefit-risk assessment to case studies on natural foods.

PubMed

Watzl, Bernhard; Gelencsér, Eva; Hoekstra, Jeljer; Kulling, Sabine; Lydeking-Olsen, Eva; Rowland, Ian; Schilter, Benoît; van Klaveren, Jakob; Chiodini, Alessandro

2012-11-01

There is evidence that consumption of fish, especially oily fish, has substantial beneficial effects on health. In particular an inverse relationship of oily fish intake to coronary heart disease incidence has been established. These beneficial effects are ascribed to fish oil components including long chain ω-3 polyunsaturated fatty acids. On the other hand it should be noted that oily fish also contains hazardous substances such as dioxins, PCBs and methylmercury. Soy consumption has been associated with potential beneficial and adverse effects. The claimed benefits include reduced risk of cardiovascular disease; osteoporosis, breast and prostate cancer whereas potential adverse effects include impaired thyroid function, disruption of sex hormone levels, changes in reproductive function and increased breast cancer risk The two cases of natural foods highlight the need to consider both risks and benefits in order to establish the net health impact associated to the consumption of specific food products. Within the Sixth Framework programme of the European Commission, the BRAFO project was funded to develop a framework that allows for the quantitative comparison of human health risks and benefits in relation to foods and food compounds. This paper describes the application of the developed framework to two natural foods, farmed salmon and soy protein. We conclude that the BRAFO methodology is highly applicable to natural foods. It will help the benefit-risk managers in selecting the appropriate dietary recommendations for the population. Copyright © 2011 ILSI Europe. Published by Elsevier Ltd.. All rights reserved.

Food additives

MedlinePlus

... or natural. Natural food additives include: Herbs or spices to add flavor to foods Vinegar for pickling ... Certain colors improve the appearance of foods. Many spices, as well as natural and man-made flavors, ...

Revealing Nature’s Synthetic Potential Through the Study of Ribosomal Natural Product Biosynthesis

PubMed Central

Dunbar, Kyle L.; Mitchell, Douglas A.

2013-01-01

Ribosomally synthesized posttranslationally modified peptides (RiPPs) are a rapidly growing class of natural products with diverse structures and activities. In recent years, a great deal of progress has been made in elucidating the biosynthesis of various RiPP family members. As with the study of nonribosomal peptide and polyketide biosynthetic enzymes, these investigations have led to the discovery of entirely new biological chemistry. With each unique enzyme investigated, a more complex picture of Nature’s synthetic potential is revealed. This review focuses on recent reports (since 2008) that have changed the way that we think about ribosomal natural product biosynthesis and the enzymology of complex bond-forming reactions. PMID:23286465

Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods.

PubMed

Linares, Daniel M; Gómez, Carolina; Renes, Erica; Fresno, José M; Tornadijo, María E; Ross, R P; Stanton, Catherine

2017-01-01

Consumer interest in healthy lifestyle and health-promoting natural products is a major driving force for the increasing global demand of biofunctional dairy foods. A number of commercial sources sell synthetic formulations of bioactive substances for use as dietary supplements. However, the bioactive-enrichment of health-oriented foods by naturally occurring microorganisms during dairy fermentation is in increased demand. While participating in milk fermentation, lactic acid bacteria can be exploited in situ as microbial sources for naturally enriching dairy products with a broad range of bioactive components that may cover different health aspects. Several of these bioactive metabolites are industrially and economically important, as they are claimed to exert diverse health-promoting activities on the consumer, such as anti-hypertensive, anti-inflammatory, and anti-diabetic, anti-oxidative, immune-modulatory, anti-cholesterolemic, or microbiome modulation. This review aims at discussing the potential of these health-supporting bacteria as starter or adjunct cultures for the elaboration of dairy foods with a broad spectrum of new functional properties and added value.

Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods

PubMed Central

Linares, Daniel M.; Gómez, Carolina; Renes, Erica; Fresno, José M.; Tornadijo, María E.; Ross, R. P.; Stanton, Catherine

2017-01-01

Consumer interest in healthy lifestyle and health-promoting natural products is a major driving force for the increasing global demand of biofunctional dairy foods. A number of commercial sources sell synthetic formulations of bioactive substances for use as dietary supplements. However, the bioactive-enrichment of health-oriented foods by naturally occurring microorganisms during dairy fermentation is in increased demand. While participating in milk fermentation, lactic acid bacteria can be exploited in situ as microbial sources for naturally enriching dairy products with a broad range of bioactive components that may cover different health aspects. Several of these bioactive metabolites are industrially and economically important, as they are claimed to exert diverse health-promoting activities on the consumer, such as anti-hypertensive, anti-inflammatory, and anti-diabetic, anti-oxidative, immune-modulatory, anti-cholesterolemic, or microbiome modulation. This review aims at discussing the potential of these health-supporting bacteria as starter or adjunct cultures for the elaboration of dairy foods with a broad spectrum of new functional properties and added value. PMID:28572792

Recognition of extended linear and cyclised polyketide mimics by a type II acyl carrier protein† †Electronic supplementary information (ESI) available: Detailed experimental procedures and characterisation data for all new compounds, additional spectra and structural statistics for derivatised ACP three-dimensional structures. See DOI: 10.1039/c5sc03864b Click here for additional data file.

PubMed Central

Dong, Xu; Bailey, Christopher D.; Williams, Christopher; Crosby, John; Simpson, Thomas J.

2016-01-01

Polyketides are secondary metabolites which display both valuable pharmaceutical and agrochemical properties. Biosynthesis is performed by polyketide synthases (PKSs), and the acyl carrier protein (ACP), a small acidic protein, that transports the growing polyketide chain and is essential for activity. Here we report the synthesis of two aromatic probes and a linear octaketide mimic that have been tethered to actinorhodin ACP. These experiments were aimed at probing the ACP's capacity to sequester a non-polar versus a phenolic aromatic ring (that more closely mimics a polyketide intermediate) as well as investigations with extended polyketide chain surrogates. The binding of these mimics has been assessed using high-resolution solution NMR studies and high-resolution structure determination. These results reveal that surprisingly a PKS ACP is able to bind and sequester a bulky non-polar substrate containing an aromatic ring in a fatty acid type binding mode, but the introduction of even a small degree of polarity favours a markedly different association at a surface site that is distinct from that employed by fatty acid ACPs. PMID:28936328

Characterization of a polyketide synthase in Aspergillus niger whose product is a precursor for both dihydroxynaphthalene (DHN) melanin and naphtho-γ-pyrone.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiang, Yi Ming; Meyer, Kristen M; Praseuth, Michael

2010-12-06

The genome sequencing of the fungus Aspergillus niger, an industrial workhorse, uncovered a large cache of genes encoding enzymes thought to be involved in the production of secondary metabolites yet to be identified. Identification and structural characterization of many of these predicted secondary metabolites are hampered by their low concentration relative to the known A. niger metabolites such as the naphtho-γ-pyrone family of polyketides. We deleted a nonreducing PKS gene in A. niger strain ATCC 11414, a daughter strain of A. niger ATCC strain 1015 whose genome was sequenced by the DOE Joint Genome Institute. This PKS encoding gene ismore » a predicted ortholog of alb1 from Aspergillus fumigatus which is responsible for production of YWA1, a precursor of fungal DHN melanin. Our results show that the A. niger alb1 PKS is responsible for the production of the polyketide precursor for DHN melanin biosynthesis. Deletion of alb1 elimnates the production of major metabolites, naphtho-γ-pyrones. The generation of an A. niger strain devoid of naphtho-γ-pyrones will greatly facilitate the elucidation of cryptic biosynthetic pathways in this organism.« less

Structural and evolutionary relationships of “AT-less” type I polyketide synthase ketosynthases

PubMed Central

Lohman, Jeremy R.; Ma, Ming; Osipiuk, Jerzy; Nocek, Boguslaw; Kim, Youngchang; Chang, Changsoo; Cuff, Marianne; Mack, Jamey; Bigelow, Lance; Li, Hui; Endres, Michael; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N.; Shen, Ben

2015-01-01

Acyltransferase (AT)-less type I polyketide synthases (PKSs) break the type I PKS paradigm. They lack the integrated AT domains within their modules and instead use a discrete AT that acts in trans, whereas a type I PKS module minimally contains AT, acyl carrier protein (ACP), and ketosynthase (KS) domains. Structures of canonical type I PKS KS-AT didomains reveal structured linkers that connect the two domains. AT-less type I PKS KSs have remnants of these linkers, which have been hypothesized to be AT docking domains. Natural products produced by AT-less type I PKSs are very complex because of an increased representation of unique modifying domains. AT-less type I PKS KSs possess substrate specificity and fall into phylogenetic clades that correlate with their substrates, whereas canonical type I PKS KSs are monophyletic. We have solved crystal structures of seven AT-less type I PKS KS domains that represent various sequence clusters, revealing insight into the large structural and subtle amino acid residue differences that lead to unique active site topologies and substrate specificities. One set of structures represents a larger group of KS domains from both canonical and AT-less type I PKSs that accept amino acid-containing substrates. One structure has a partial AT-domain, revealing the structural consequences of a type I PKS KS evolving into an AT-less type I PKS KS. These structures highlight the structural diversity within the AT-less type I PKS KS family, and most important, provide a unique opportunity to study the molecular evolution of substrate specificity within the type I PKSs. PMID:26420866

Hypersensitivity reactions to food colours with special reference to the natural colour annatto extract (butter colour).

PubMed

Mikkelsen, H; Larsen, J C; Tarding, F

1978-01-01

It is well known that synthetic food colours especially some azo dyes can provoke hypersensitivity reactions such as urticaria, angioneurotic oedema, and astma (Michaëlsson and Juhlin, 1973, Granholt and Thune, 1975). Natural food colours are scarcely investigated with respect to potential allergic properties. Annatto extract, a commonly used food colour in edible fats e.g. butter, has been tested in patients. Among 61 consecutive patients suffereing from chornic urticaria and/or angioneurotic oedema 56 patients were orally provoked by annatto extract during elimination diet. Challenge was performed with a dose equivalent to the amount used in 25 grammes of butter. Twentysix per cent of the patients reacted to this colour 4 hours (SD: 2,6) after intake. Similar challenges with synthetic dyes showed the following results: Tartrazine 11%, Sunset Yellow FCF 17%, Food Red 17 16%, Amaranth 9%, Ponceau 4 R 15%, Erythrosine 12% and Brillant Blue FCF 14%. The present study indicates that natural food colours may induce hypersensitivity reactions as frequent as synthetic dyes.

Confluence of structural and chemical biology: plant polyketide synthases as biocatalysts for a bio-based future.

PubMed

Stewart, Charles; Vickery, Christopher R; Burkart, Michael D; Noel, Joseph P

2013-06-01

Type III plant polyketide synthases (PKSs) biosynthesize a dazzling array of polyphenolic products that serve important roles in both plant and human health. Recent advances in structural characterization of these enzymes and new tools from the field of chemical biology have facilitated exquisite probing of plant PKS iterative catalysis. These tools have also been used to exploit type III PKSs as biocatalysts to generate new chemicals. Going forward, chemical, structural and biochemical analyses will provide an atomic resolution understanding of plant PKSs and will serve as a springboard for bioengineering and scalable production of valuable molecules in vitro, by fermentation and in planta. Copyright © 2013 Elsevier Ltd. All rights reserved.

Natural Products from the Lithistida: A Review of the Literature since 2000

PubMed Central

Winder, Priscilla L.; Pomponi, Shirley A.; Wright, Amy E.

2011-01-01

Lithistid sponges are known to produce a diverse array of compounds ranging from polyketides, cyclic and linear peptides, alkaloids, pigments, lipids, and sterols. A majority of these structurally complex compounds have very potent and interesting biological activities. It has been a decade since a thorough review has been published that summarizes the literature on the natural products reported from this amazing sponge order. This review provides an update on the current taxonomic classification of the Lithistida, describes structures and biological activities of 131 new natural products, and discusses highlights from the total syntheses of 16 compounds from marine sponges of the Order Lithistida providing a compilation of the literature since the last review published in 2002. PMID:22363244

Polyketide-Terpene Hybrid Metabolites from an Endolichenic Fungus Pestalotiopsis sp.

PubMed Central

Ding, Gang; Wang, Hai-Ying; Guo, Yu-Hua; Shang, Hai

2017-01-01

Five new polyketide-terpene hybrid metabolites (1–5) with highly functionalized groups, together with six known derivatives (6–11), were isolated from the endolichenic fungus Pestalotiopsis sp. Their structures were elucidated by extensive NMR experiments including 1H, 13C, HMQC, COSY, and HMBC. The relative configurations of the new compounds were determined by analysis of coupling constants and ROESY correlations. The absolute configurations especially the secondary alcohol at C-15 in 1 and secondary alcohol at C-14 in 5 were established via the CD experiments of the in situ formed [Rh2(OCOCF3)4] complex with the acetonide derivatives. These compounds were tested for their inhibition activity against six plant pathogens. Compounds 1 and 5 exhibited pronounced efficiency against Fusarium oxysporum, and compounds 5 and 6 potently inhibited Fusarium gramineum with MIC value of 8 µg/mL, which revealed the plausible ecological role of endolichenic fungus in providing chemical protection for its host lichen in the fungus-plant relationship. The biosynthetic pathway of compounds 1–11 was postulated for the first time, which paved the way for its further biosynthesis research. PMID:28593175

Polyketide-Terpene Hybrid Metabolites from an Endolichenic Fungus Pestalotiopsis sp.

PubMed

Yuan, Chao; Ding, Gang; Wang, Hai-Ying; Guo, Yu-Hua; Shang, Hai; Ma, Xiao-Jun; Zou, Zhong-Mei

2017-01-01

Five new polyketide-terpene hybrid metabolites ( 1 - 5 ) with highly functionalized groups, together with six known derivatives ( 6 - 11 ), were isolated from the endolichenic fungus Pestalotiopsis sp. Their structures were elucidated by extensive NMR experiments including 1 H, 13 C, HMQC, COSY, and HMBC. The relative configurations of the new compounds were determined by analysis of coupling constants and ROESY correlations. The absolute configurations especially the secondary alcohol at C-15 in 1 and secondary alcohol at C-14 in 5 were established via the CD experiments of the in situ formed [Rh 2 (OCOCF 3 ) 4 ] complex with the acetonide derivatives. These compounds were tested for their inhibition activity against six plant pathogens. Compounds 1 and 5 exhibited pronounced efficiency against Fusarium oxysporum , and compounds 5 and 6 potently inhibited Fusarium gramineum with MIC value of 8  µ g/mL, which revealed the plausible ecological role of endolichenic fungus in providing chemical protection for its host lichen in the fungus-plant relationship. The biosynthetic pathway of compounds 1 - 11 was postulated for the first time, which paved the way for its further biosynthesis research.

Polyketide family of novel antibacterial 7-O-methyl-5'-hydroxy-3'-heptenoate-macrolactin from seaweed-associated Bacillus subtilis MTCC 10403.

PubMed

Chakraborty, Kajal; Thilakan, Bini; Raola, Vamshi Krishna

2014-12-17

Seaweed-associated heterotrophic bacterial communities were screened to isolate potentially useful antimicrobial strains, which were characterized by phylogenetic analysis. The bacteria were screened for the presence of metabolite genes involved in natural product biosynthetic pathway, and the structural properties of secondary metabolites were correlated with the genes. Bioactivity-guided isolation of polyene antibiotic 7-O-methyl-5'-hydroxy-3'-heptenoate-macrolactin from Bacillus subtilis MTCC10403 associated with seaweed Anthophycus longifolius using mass spectrometry and extensive 2D-NMR studies was carried out. The newly isolated macrolactin compound is a bactericidal antibiotic with broad spectrum activity against human opportunistic clinical pathogens. The biosynthetic pathway of 7-O-methyl-5'-hydroxy-3'-heptenoate-macrolactin by means of a stepwise, decarboxylative condensation pathway established the PKS-assisted biosynthesis of the parent macrolactin and the side-chain 5-hydroxyhept-3-enoate moiety attached to the macrolactin ring system at C-7. Antimicrobial activity analysis combined with the results of amplifying genes encoding for polyketide synthetase and nonribosomal peptide synthetase showed that seaweed-associated bacteria had broad-spectrum antimicrobial activity. The present work may have an impact on the exploitation of macrolactins for pharmaceutical and biotechnological applications.

Antimicrobial peptides as natural bio-preservative to enhance the shelf-life of food.

PubMed

Rai, Mahendra; Pandit, Raksha; Gaikwad, Swapnil; Kövics, György

2016-09-01

Antimicrobial peptides (AMPs) are diverse group of natural proteins present in animals, plants, insects and bacteria. These peptides are responsible for defense of host from pathogenic organisms. Chemical, enzymatic and recombinant techniques are used for the synthesis of antimicrobial peptides. These peptides have been found to be an alternative to the chemical preservatives. Currently, nisin is the only antimicrobial peptide, which is widely utilized in the preservation of food. Antimicrobial peptides can be used alone or in combination with other antimicrobial, essential oils and polymeric nanoparticles to enhance the shelf-life of food. This review presents an overview on different types of antimicrobial peptides, purification techniques, mode of action and application in food preservation.

Natural dibenzo-α-pyrones and their bioactivities.

PubMed

Mao, Ziling; Sun, Weibo; Fu, Linyun; Luo, Haiyu; Lai, Daowan; Zhou, Ligang

2014-04-22

Natural dibenzo-α-pyrones are an important group of metabolites derived from fungi, mycobionts, plants and animal feces. They exhibit a variety of biological activities such as toxicity on human and animals, phytotoxicity as well as cytotoxic, antioxidant, antiallergic, antimicrobial, antinematodal, and acetylcholinesterase inhibitory properties. Dibenzo-α-pyrones are biosynthesized via the polyketide pathway in microorganisms or metabolized from plant-derived ellagitannins and ellagic acid by intestinal bacteria. At least 53 dibenzo-α-pyrones have been reported in the past few decades. This mini-review aims to briefly summarize the occurrence, biosynthesis, biotransformation, as well as their biological activities and functions. Some considerations related to synthesis, production and applications of dibenzo-α-pyrones are also discussed.

Natural food toxins of bacterial origin

USDA-ARS?s Scientific Manuscript database

One in six people in the US acquire a foodborne illness each year. Food poisoning is a general term used to describe the physiological effects caused by ingestion of contaminated food or water. The effects of ingesting contaminated food range from short-lived symptoms such as vomiting and diarrhea...

Natural antioxidant activity of commonly consumed plant foods in India: effect of domestic processing.

PubMed

Sreeramulu, D; Reddy, C V K; Chauhan, Anitha; Balakrishna, N; Raghunath, M

2013-01-01

Phytochemicals protect against oxidative stress which in turn helps in maintaining the balance between oxidants and antioxidants. In recent times natural antioxidants are gaining considerable interest among nutritionists, food manufacturers, and consumers because of their perceived safety, potential therapeutic value, and long shelf life. Plant foods are known to protect against degenerative diseases and ageing due to their antioxidant activity (AOA) attributed to their high polyphenolic content (PC). Data on AOA and PC of Indian plant foods is scanty. Therefore we have determined the antioxidant activity in 107 commonly consumed Indian plant foods and assessed their relation to their PC. Antioxidant activity is presented as the range of values for each of the food groups. The foods studied had good amounts of PC and AOA although they belonged to different food groups. Interestingly, significant correlation was observed between AOA (DPPH and FRAP) and PC in most of the foods, corroborating the literature that polyphenols are potent antioxidants and that they may be important contributors to the AOA of the plant foods. We have also observed that common domestic methods of processing may not affect the PC and AOA of the foods studied in general. To the best of our knowledge, these are the first results of the kind in commonly consumed Indian plant foods.

Nature Study Tips: Native American Foods.

ERIC Educational Resources Information Center

Russell, Helen Ross

1984-01-01

Discusses Native American foods, focusing on Native American cultivated crops, methods of cooking, and methods of preserving food. Includes suggestions for 19 classroom activities, including collecting wild plants used as food, gathering/drying and eating various wild plants and plant products (such as acorns and corn), and making a garden. (JN)

Hand-held dynamic visual noise reduces naturally occurring food cravings and craving-related consumption.

PubMed

Kemps, Eva; Tiggemann, Marika

2013-09-01

This study demonstrated the applicability of the well-established laboratory task, dynamic visual noise, as a technique for reducing naturally occurring food cravings and subsequent food intake. Dynamic visual noise was delivered on a hand-held computer device. Its effects were assessed within the context of a diary study. Over a 4-week period, 48 undergraduate women recorded their food cravings and consumption. Following a 2-week baseline, half the participants watched the dynamic visual noise display whenever they experienced a food craving. Compared to a control group, these participants reported less intense cravings. They were also less likely to eat following a craving and consequently consumed fewer total calories following craving. These findings hold promise for curbing unwanted food cravings and craving-driven consumption in real-world settings. Copyright © 2013 Elsevier Ltd. All rights reserved.

Marine Natural Products as Models to Circumvent Multidrug Resistance.

PubMed

Long, Solida; Sousa, Emília; Kijjoa, Anake; Pinto, Madalena M M

2016-07-08

Multidrug resistance (MDR) to anticancer drugs is a serious health problem that in many cases leads to cancer treatment failure. The ATP binding cassette (ABC) transporter P-glycoprotein (P-gp), which leads to premature efflux of drugs from cancer cells, is often responsible for MDR. On the other hand, a strategy to search for modulators from natural products to overcome MDR had been in place during the last decades. However, Nature limits the amount of some natural products, which has led to the development of synthetic strategies to increase their availability. This review summarizes the research findings on marine natural products and derivatives, mainly alkaloids, polyoxygenated sterols, polyketides, terpenoids, diketopiperazines, and peptides, with P-gp inhibitory activity highlighting the established structure-activity relationships. The synthetic pathways for the total synthesis of the most promising members and analogs are also presented. It is expected that the data gathered during the last decades concerning their synthesis and MDR-inhibiting activities will help medicinal chemists develop potential drug candidates using marine natural products as models which can deliver new ABC transporter inhibitor scaffolds.

Serum sterol responses to increasing plant sterol intake from natural foods in the Mediterranean diet.

PubMed

Escurriol, Verónica; Cofán, Montserrat; Serra, Mercè; Bulló, Mónica; Basora, Josep; Salas-Salvadó, Jordi; Corella, Dolores; Zazpe, Itziar; Martínez-González, Miguel A; Ruiz-Gutiérrez, Valentina; Estruch, Ramón; Ros, Emilio

2009-09-01

Phytosterols in natural foods are thought to inhibit cholesterol absorption. The Mediterranean diet is rich in phytosterol-containing plant foods. To assess whether increasing phytosterol intake from natural foods was associated with a cholesterol-lowering effect in a substudy of a randomized trial of nutritional intervention with Mediterranean diets for primary cardiovascular prevention (PREDIMED study). One hundred and six high cardiovascular risk subjects assigned to two Mediterranean diets supplemented with virgin olive oil (VOO) or nuts, which are phytosterol-rich foods, or advice on a low-fat diet. Outcomes were 1-year changes in nutrient intake and serum levels of lipids and non-cholesterol sterols. Average phytosterol intake increased by 76, 158 and 15 mg/day in participants assigned VOO, nuts and low-fat diets, respectively. Compared to participants in the low-fat diet group, changes in outcome variables were observed only in those in the Mediterranean diet with nuts group, with increases in intake of fibre, polyunsaturated fatty acids and phytosterols (P < 0.020, all) and significant (P < 0.05) reductions of LDL-cholesterol (0.27 mmol/l or 8.3%) and the LDL/HDL-cholesterol ratio (0.29 mmol/l or 11.5%). Variations in saturated fat, cholesterol or fibre intake were unrelated to LDL-cholesterol changes. In the whole group, changes in serum sitosterol-to-cholesterol, which reflect those of dietary phytosterol intake and absorption, correlated inversely to LDL-cholesterol changes (r = -0.256; P = 0.008). In multivariate analyses, baseline LDL-cholesterol, increases in serum sitosterol ratios and statin use were independently associated with LDL-cholesterol reductions. Small amounts of phytosterols in natural foods appear to be bioactive in cholesterol lowering.

Comprehensive in Vitro Analysis of Acyltransferase Domain Exchanges in Modular Polyketide Synthases and Its Application for Short-Chain Ketone Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuzawa, Satoshi; Deng, Kai; Wang, George

2016-08-22

Type I modular polyketide synthases (PKSs) are polymerases that utilize acyl-CoAs as substrates. Each polyketide elongation reaction is catalyzed by a set of protein domains called a module. Each module usually contains an acyltransferase (AT) domain, which determines the specific acyl-CoA incorporated into each condensation reaction. Although a successful exchange of individual AT domains can lead to the biosynthesis of a large variety of novel compounds, hybrid PKS modules often show significantly decreased activities. Using monomodular PKSs as models, we have systematically analyzed in this paper the segments of AT domains and associated linkers in AT exchanges in vitro andmore » have identified the boundaries within a module that can be used to exchange AT domains while maintaining protein stability and enzyme activity. Importantly, the optimized domain boundary is highly conserved, which facilitates AT domain replacements in most type I PKS modules. To further demonstrate the utility of the optimized AT domain boundary, we have constructed hybrid PKSs to produce industrially important short-chain ketones. Our in vitro and in vivo analysis demonstrated production of predicted ketones without significant loss of activities of the hybrid enzymes. Finally, these results greatly enhance the mechanistic understanding of PKS modules and prove the benefit of using engineered PKSs as a synthetic biology tool for chemical production.« less

Urban wild boars prefer fragmented areas with food resources near natural corridors.

PubMed

Castillo-Contreras, Raquel; Carvalho, João; Serrano, Emmanuel; Mentaberre, Gregorio; Fernández-Aguilar, Xavier; Colom, Andreu; González-Crespo, Carlos; Lavín, Santiago; López-Olvera, Jorge R

2018-02-15

Wild boar populations are expanding throughout the world and intruding into periurban and urban areas. In the last years, wild boar has colonized several European cities, including our study area, the city of Barcelona. It is required to identify the main factors driving wild boar into urban areas prior to establish management measures. We built Boosted Regression Trees (BRT) using 3148 wild boar presences registered in the urban area of Barcelona from 2010 to 2014 to identify the variables correlated with these presences. The variables analysed included proxies for distance to source population, urban food resources, climate and urban habitat structure. Wild boars enter the urban area from close natural habitat using corridors such as streams, preferably in fragmented urban environment, looking for food such as urban green areas or dry pet food from cat colonies. Wild boar presence is higher in spring possibly due to the births of piglets and the dispersion of yearlings during that season, and also when natural resources in the Mediterranean habitat fail to satisfy the nutritional requirements of the wild boar population during the summer season. Management measures derived from this study are currently being applied in the city of Barcelona, including vegetation clearings in the wild boar entrance areas and an awareness campaign aimed at reducing the anthropogenic food availability for wild boars. The methodology used can be applied to other cities with wild boar or even other wildlife species issues. The comparison between the factors attracting wild boars into different urban areas would be helpful to understand the global phenomenon. Copyright © 2017 Elsevier B.V. All rights reserved.

Mycobacterial polyketide-associated proteins are acyltransferases: Proof of principle with Mycobacterium tuberculosis PapA5

PubMed Central

Onwueme, Kenolisa C.; Ferreras, Julian A.; Buglino, John; Lima, Christopher D.; Quadri, Luis E. N.

2004-01-01

Mycobacterium tuberculosis (Mt) produces complex virulence-enhancing lipids with scaffolds consisting of phthiocerol and phthiodiolone dimycocerosate esters (PDIMs). Sequence analysis suggested that PapA5, a so-called polyketide-associated protein (Pap) encoded in the PDIM synthesis gene cluster, as well as PapA5 homologs found in Mt and other species, are a subfamily of acyltransferases. Studies with recombinant protein confirmed that PapA5 is an acetyltransferase. Deletion analysis in Mt demonstrated that papA5 is required for PDIM synthesis. We propose that PapA5 catalyzes diesterification of phthiocerol and phthiodiolone with mycocerosate. These studies present the functional characterization of a Pap and permit inferences regarding roles of other Paps in the synthesis of complex lipids, including the antibiotic rifamycin. PMID:15070765

Spent yeast as natural source of functional food additives

PubMed

Rakowska, Rita; Sadowska, Anna; Dybkowska, Ewa; Świderski, Franciszek

as natural food additives that are functional.

Gibepyrone Biosynthesis in the Rice Pathogen Fusarium fujikuroi Is Facilitated by a Small Polyketide Synthase Gene Cluster*

PubMed Central

Janevska, Slavica; Arndt, Birgit; Niehaus, Eva-Maria; Burkhardt, Immo; Rösler, Sarah M.; Brock, Nelson L.; Humpf, Hans-Ulrich; Dickschat, Jeroen S.; Tudzynski, Bettina

2016-01-01

The 2H-pyran-2-one gibepyrone A and its oxidized derivatives gibepyrones B–F have been isolated from the rice pathogenic fungus Fusarium fujikuroi already more than 20 years ago. However, these products have not been linked to the respective biosynthetic genes, and therefore, their biosynthesis has not yet been analyzed on a molecular level. Feeding experiments with isotopically labeled precursors clearly supported a polyketide origin for the formal monoterpenoid gibepyrone A, whereas the terpenoid pathway could be excluded. Targeted gene deletion verified that the F. fujikuroi polyketide synthase PKS13, designated Gpy1, is responsible for gibepyrone A biosynthesis. Next to Gpy1, the ATP-binding cassette transporter Gpy2 is encoded by the gibepyrone gene cluster. Gpy2 was shown to have only a minor impact on the actual efflux of gibepyrone A out of the cell. Instead, we obtained evidence that Gpy2 is involved in gene regulation as it represses GPY1 gene expression. Thus, GPY1 was up-regulated and gibepyrone A production was enhanced both extra- and intracellularly in Δgpy2 mutants. Furthermore, expression of GPY genes is strictly repressed by members of the fungus-specific velvet complex, Vel1, Vel2, and Lae1, whereas Sge1, a major regulator of secondary metabolism in F. fujikuroi, affects gibepyrone biosynthesis in a positive manner. The gibepyrone A derivatives gibepyrones B and D were shown to be produced by cluster-independent P450 monooxygenases, probably to protect the fungus from the toxic product. In contrast, the formation of gibepyrones E and F from gibepyrone A is a spontaneous process and independent of enzymatic activity. PMID:27856636

Tracking spore-forming bacteria in food: from natural biodiversity to selection by processes.

PubMed

Postollec, Florence; Mathot, Anne-Gabrielle; Bernard, Muriel; Divanac'h, Marie-Laure; Pavan, Sonia; Sohier, Danièle

2012-08-01

Sporeforming bacteria are ubiquitous in the environment and exhibit a wide range of diversity leading to their natural prevalence in foodstuff. The state of the art of sporeformer prevalence in ingredients and food was investigated using a multiparametric PCR-based tool that enables simultaneous detection and identification of various genera and species mostly encountered in food, i.e., Alicyclobacillus, Anoxybacillus flavithermus, Bacillus, B. cereus group, B. licheniformis, B. pumilus, B. sporothermodurans, B. subtilis, Brevibacillus laterosporus, Clostridium, Geobacillus stearothermophilus, Moorella and Paenibacillus species. In addition, 16S rDNA sequencing was used to extend identification to other possibly present contaminants. A total of 90 food products, with or without visible trace of spoilage were analysed, i.e., 30 egg-based products, 30 milk and dairy products and 30 canned food and ingredients. Results indicated that most samples contained one or several of the targeted genera and species. For all three tested food categories, 30 to 40% of products were contaminated with both Bacillus and Clostridium. The percentage of contaminations associated with Clostridium or Bacillus represented 100% in raw materials, 72% in dehydrated ingredients and 80% in processed foods. In the last two product types, additional thermophilic contaminants were identified (A. flavithermus, Geobacillus spp., Thermoanaerobacterium spp. and Moorella spp.). These results suggest that selection, and therefore the observed (re)-emergence of unexpected sporeforming contaminants in food might be favoured by the use of given food ingredients and food processing technologies. Copyright © 2012 Elsevier B.V. All rights reserved.

The "natural" aversion: the FDA's reluctance to define a leading food-industry marketing claim, and the pressing need for a workable rule.

PubMed

Farris, April L

2010-01-01

As of 2009, the "natural foods" industry has become a 22.3 billion dollar giant and "all-natural" is the second-leading marketing claim for all new food products. Even in such a flourishing market, the Food and Drug Administration (FDA) has never defined the term "natural" through rulemaking. FDA and the U.S. Department of Agriculture (USDA) have instead created separate, non-identical policy statements governing the use of the term "natural," and FDA has abandoned efforts to define "natural" through rulemaking in the face of more pressing priorities. In absence of any governing federal standard, consumer advocacy groups and warring food industries have attempted to define "natural" to fit their preferences through high-stakes litigation of state law claims, leaving courts free to apply diverging standards without the expertise of FDA. Recent case law from federal district courts and the Supreme Court leaves little hope that FDA's current policy statement will preempt state law causes of action. To prevent a potential patchwork of definitions varying by state, and to create a legitimate standard resting on informed scientific expertise rather than consumer whims, FDA should engage in rulemaking to define the term "natural." This paper concludes by sketching potential formulations for such a rule based on FDA's previous successful rule-making ventures and standards used by natural foods retailers.

The extent and nature of television food advertising to children in Xi'an, China.

PubMed

Li, Danyang; Wang, Ting; Cheng, Yue; Zhang, Min; Yang, Xue; Zhu, Zhonghai; Liu, Danli; Yang, Wenfang; Zeng, Lingxia

2016-08-11

To explore the extent and nature of television food advertising especially unhealthy food advertising to primary school children in Xi'an, China. Television data were recorded for 2 weekdays and 2 weekend days between 6:00 and 22:00 during May and June in 2012 from a total of five television channels most popular with children in Xi'an. Pearson χ (2) tests and logistic regression were applied to determine differences in the proportion of healthy food, unhealthy food and miscellaneous food advertisements for different channels, programs, dates, viewing periods and the use of persuasive marketing tactics. Of the 5527 advertisements transcribed, 25.5 % were for food, among which 48.1 % were considered to be unhealthy. The frequency of food advertisements was 6 per hour per channel, including 3 unhealthy food advertisements. Compared with healthy and miscellaneous food advertisements, more unhealthy food advertisements were shown during afternoon, weekends and children's non-peak viewing times as well as on children's television channels, central television channels and non-children's programmes. Unhealthy foods contributed the highest proportion of all food advertisements containing promotional characters (51.7 %) and premium offers (59.1 %). Both promotional characters and premium offers appeared more on non-children's television channels. The majority of food advertisements were for unhealthy food. More unhealthy food ads were shown in children's non-peak time and afternoon as well as non-children's channels. More children-oriented persuasive marketing tactics were used in unhealthy food ads especially in non-children's channels. Therefore, intervening in the entrance of unhealthy foods into the market and establishing regulations related to food advertising especially unhealthy food advertisements are important strategies to prevent children's exposure to unhealthy food and childhood obesity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuzawa, Satoshi; Keasling, Jay D.; Katz, Leonard

Complex polyketides comprise a large number of natural products that have broad application in medicine and agriculture. They are produced in bacteria and fungi from large enzyme complexes named type I modular polyketide synthases (PKSs) that are composed of multifunctional polypeptides containing discrete enzymatic domains organized into modules. The modular nature of PKSs has enabled a multitude of efforts to engineer the PKS genes to produce novel polyketides of predicted structure. Finally, we have repurposed PKSs to produce a number of short-chain mono- and di-carboxylic acids and ketones that could have applications as fuels or industrial chemicals.

Comparative Thermal Degradation Patterns of Natural Yellow Colorants Used in Foods.

PubMed

Giménez, Pedro J; Fernández-López, José A; Angosto, José M; Obón, José M

2015-12-01

There is a great interest in natural yellow colorants due to warnings issued about certain yellow food colorings of synthetic origin. However, no comparative studies have been reported of their thermal stability. For this reason, the thermal stabilities of six natural yellow colorants used in foods--lutein, riboflavin, curcumin, ß-carotene, gardenia yellow and Opuntia betaxanthins--were studied in simple solutions over a temperature range 30-90 °C. Spectral properties and visual color were investigated during 6 h of heat treatment. Visual color was monitored from the CIEL*a*b* parameters. The remaining absorbance at maximum wavelength and the total color difference were used to quantify color degradation. The rate of color degradation increased as the temperature rose. The results showed that the thermal degradation of the colorants followed a first-order reaction kinetics. The reaction rate constants and half-life periods were determined as being central to understanding the color degradation kinetics. The temperature-dependent degradation was adequately modeled on the Arrhenius equation. Activation energies ranged from 3.2 kJmol(-1) (lutein) to 43.7 kJmol(-1) (Opuntia betaxanthins). ß-carotene and lutein exhibited high thermal stability, while betaxanthins and riboflavin degraded rapidly as temperature increased. Gardenia yellow and curcumin were in an intermediate position.

Molecular architectures of benzoic acid-specific type III polyketide synthases

PubMed Central

Stewart, Charles; Woods, Kate; Macias, Greg; Allan, Andrew C.; Noel, Joseph P.

2017-01-01

Biphenyl synthase and benzophenone synthase constitute an evolutionarily distinct clade of type III polyketide synthases (PKSs) that use benzoic acid-derived substrates to produce defense metabolites in plants. The use of benzoyl-CoA as an endogenous substrate is unusual for type III PKSs. Moreover, sequence analyses indicate that the residues responsible for the functional diversification of type III PKSs are mutated in benzoic acid-specific type III PKSs. In order to gain a better understanding of structure–function relationships within the type III PKS family, the crystal structures of biphenyl synthase from Malus × domestica and benzophenone synthase from Hypericum androsaemum were compared with the structure of an archetypal type III PKS: chalcone synthase from Malus × domestica. Both biphenyl synthase and benzophenone synthase contain mutations that reshape their active-site cavities to prevent the binding of 4-coumaroyl-CoA and to favor the binding of small hydrophobic substrates. The active-site cavities of biphenyl synthase and benzophenone synthase also contain a novel pocket associated with their chain-elongation and cyclization reactions. Collectively, these results illuminate structural determinants of benzoic acid-specific type III PKSs and expand the understanding of the evolution of specialized metabolic pathways in plants. PMID:29199980

Role of Modular Polyketide Synthases in the Production of Polyether Ladder Compounds in Ciguatoxin-Producing Gambierdiscus polynesiensis and G. excentricus (Dinophyceae).

PubMed

Kohli, Gurjeet S; Campbell, Katrina; John, Uwe; Smith, Kirsty F; Fraga, Santiago; Rhodes, Lesley L; Murray, Shauna A

2017-09-01

Gambierdiscus, a benthic dinoflagellate, produces ciguatoxins that cause the human illness Ciguatera. Ciguatoxins are polyether ladder compounds that have a polyketide origin, indicating that polyketide synthases (PKS) are involved in their production. We sequenced transcriptomes of Gambierdiscus excentricus and Gambierdiscus polynesiensis and found 264 contigs encoding single domain ketoacyl synthases (KS; G. excentricus: 106, G. polynesiensis: 143) and ketoreductases (KR; G. excentricus: 7, G. polynesiensis: 8) with sequence similarity to type I PKSs, as reported in other dinoflagellates. In addition, 24 contigs (G. excentricus: 3, G. polynesiensis: 21) encoding multiple PKS domains (forming typical type I PKSs modules) were found. The proposed structure produced by one of these megasynthases resembles a partial carbon backbone of a polyether ladder compound. Seventeen contigs encoding single domain KS, KR, s-malonyltransacylase, dehydratase and enoyl reductase with sequence similarity to type II fatty acid synthases (FAS) in plants were found. Type I PKS and type II FAS genes were distinguished based on the arrangement of domains on the contigs and their sequence similarity and phylogenetic clustering with known PKS/FAS genes in other organisms. This differentiation of PKS and FAS pathways in Gambierdiscus is important, as it will facilitate approaches to investigating toxin biosynthesis pathways in dinoflagellates. © 2017 The Author(s) Journal of Eukaryotic Microbiology © 2017 International Society of Protistologists.

Potential of Food and Natural Products to Promote Endothelial and Vascular Health.

PubMed

Auger, Cyril; Said, Amissi; Nguyen, Phuong Nga; Chabert, Philippe; Idris-Khodja, Noureddine; Schini-Kerth, Valérie B

2016-07-01

Endothelial dysfunction is now well established as a pivotal early event in the development of major cardiovascular diseases including hypertension, atherosclerosis, and diabetes. The alteration of the endothelial function is often triggered by an imbalance between the endothelial formation of vasoprotective factors including nitric oxide (NO) and endothelium-dependent hyperpolarization, and an increased level of oxidative stress involving several prooxidant enzymes such as NADPH oxidase and, often also, the appearance of cyclooxygenase-derived vasoconstrictors. Preclinical studies have indicated that polyphenol-rich food and food-derived products such as grape-derived products, black and red berries, green and black teas and cocoa, and omega-3 fatty acids can trigger activating pathways in endothelial cells promoting an increased formation of nitric oxide and endothelium-dependent hyperpolarization. Moreover, intake of such food-derived products has been associated with the prevention and/or the improvement of an established endothelial dysfunction in several experimental models of cardiovascular diseases and in humans with cardiovascular diseases. This review will discuss both experimental and clinical evidences indicating that different types of food and natural products are able to promote endothelial and vascular health, as well as the underlying mechanisms.

Assessing the association between natural food folate intake and blood folate concentrations: a systematic review and Bayesian meta-analysis of trials and observational studies.

PubMed

Marchetta, Claire M; Devine, Owen J; Crider, Krista S; Tsang, Becky L; Cordero, Amy M; Qi, Yan Ping; Guo, Jing; Berry, Robert J; Rosenthal, Jorge; Mulinare, Joseph; Mersereau, Patricia; Hamner, Heather C

2015-04-10

Folate is found naturally in foods or as synthetic folic acid in dietary supplements and fortified foods. Adequate periconceptional folic acid intake can prevent neural tube defects. Folate intake impacts blood folate concentration; however, the dose-response between natural food folate and blood folate concentrations has not been well described. We estimated this association among healthy females. A systematic literature review identified studies (1 1992-3 2014) with both natural food folate intake alone and blood folate concentration among females aged 12-49 years. Bayesian methods were used to estimate regression model parameters describing the association between natural food folate intake and subsequent blood folate concentration. Seven controlled trials and 29 observational studies met the inclusion criteria. For the six studies using microbiologic assay (MA) included in the meta-analysis, we estimate that a 6% (95% Credible Interval (CrI): 4%, 9%) increase in red blood cell (RBC) folate concentration and a 7% (95% CrI: 1%, 12%) increase in serum/plasma folate concentration can occur for every 10% increase in natural food folate intake. Using modeled results, we estimate that a natural food folate intake of ≥ 450 μg dietary folate equivalents (DFE)/day could achieve the lower bound of an RBC folate concentration (~ 1050 nmol/L) associated with the lowest risk of a neural tube defect. Natural food folate intake affects blood folate concentration and adequate intakes could help women achieve a RBC folate concentration associated with a risk of 6 neural tube defects/10,000 live births.

Genetic diversity, morphological uniformity and polyketide production in dinoflagellates (Amphidinium, Dinoflagellata).

PubMed

Murray, Shauna A; Garby, Tamsyn; Hoppenrath, Mona; Neilan, Brett A

2012-01-01

Dinoflagellates are an intriguing group of eukaryotes, showing many unusual morphological and genetic features. Some groups of dinoflagellates are morphologically highly uniform, despite indications of genetic diversity. The species Amphidinium carterae is abundant and cosmopolitan in marine environments, grows easily in culture, and has therefore been used as a 'model' dinoflagellate in research into dinoflagellate genetics, polyketide production and photosynthesis. We have investigated the diversity of 'cryptic' species of Amphidinium that are morphologically similar to A. carterae, including the very similar species Amphidinium massartii, based on light and electron microscopy, two nuclear gene regions (LSU rDNA and ITS rDNA) and one mitochondrial gene region (cytochrome b). We found that six genetically distinct cryptic species (clades) exist within the species A. massartii and four within A. carterae, and that these clades differ from one another in molecular sequences at levels comparable to other dinoflagellate species, genera or even families. Using primers based on an alignment of alveolate ketosynthase sequences, we isolated partial ketosynthase genes from several Amphidinium species. We compared these genes to known dinoflagellate ketosynthase genes and investigated the evolution and diversity of the strains of Amphidinium that produce them.

Genetic Diversity, Morphological Uniformity and Polyketide Production in Dinoflagellates (Amphidinium, Dinoflagellata)

PubMed Central

Hoppenrath, Mona; Neilan, Brett A.

2012-01-01

Dinoflagellates are an intriguing group of eukaryotes, showing many unusual morphological and genetic features. Some groups of dinoflagellates are morphologically highly uniform, despite indications of genetic diversity. The species Amphidinium carterae is abundant and cosmopolitan in marine environments, grows easily in culture, and has therefore been used as a ‘model’ dinoflagellate in research into dinoflagellate genetics, polyketide production and photosynthesis. We have investigated the diversity of ‘cryptic’ species of Amphidinium that are morphologically similar to A. carterae, including the very similar species Amphidinium massartii, based on light and electron microscopy, two nuclear gene regions (LSU rDNA and ITS rDNA) and one mitochondrial gene region (cytochrome b). We found that six genetically distinct cryptic species (clades) exist within the species A. massartii and four within A. carterae, and that these clades differ from one another in molecular sequences at levels comparable to other dinoflagellate species, genera or even families. Using primers based on an alignment of alveolate ketosynthase sequences, we isolated partial ketosynthase genes from several Amphidinium species. We compared these genes to known dinoflagellate ketosynthase genes and investigated the evolution and diversity of the strains of Amphidinium that produce them. PMID:22675531

Responsibilities of the USDA-Food and Nutrition Service in Nutrition Assistance Response to Natural Disasters.

PubMed

Abernathy, Toni

2015-01-01

USDA makes sure that nutritious USDA Foods are made available to States, Indian Tribal Organizations and Emergency Feeding Organizations to help feed survivors of natural disasters and other emergencies when needed.

A natural compromise: a moderate solution to the GMO & "natural" labeling disputes.

PubMed

Amaru, Stephanie

2014-01-01

In the United States, genetically modified (GM) foods are labeled no differently from their natural counterparts, leaving consumers with no mechanism for deciphering genetically modified food content. The Food and Drug Administration (FDA) has not formally defined the term "natural," which is frequently used on food labels despite consumer confusion as to what it means. The FDA should initiate a notice and comment rulemaking addressing the narrow issue of whether use of the word "natural" should be permitted oil GM food labels. Prohibition of the use of"natural" on genetically modified foods would mitigate consumer deception regarding genetically modified food content without significantly disadvantaging genetically modified food producers.

The extent and nature of "health messages" in magazine food advertising in Australia.

PubMed

Jones, Sandra C; Andrews, Kelly L; Tapsell, Linda; Williams, Peter; McVie, Danielle

2008-01-01

To quantify the extent and nature of healthy eating messages Australian consumers are currently exposed through magazine advertising. Analysis of healthy eating messages in advertisements found in the top 30 Australian magazines between January and June 2005 was conducted. Advertisements were analysed and classified by source, subject, food category, food type, food occasion, type of claim and disease type. A total of 1,040 advertisements were identified which contained a healthy eating message; after removing duplicates, 390 advertisements were analysed. Culinary and women's magazines contained the greatest number of healthy eating messages. The most frequently occurring food category utilising a health message in an advertisement was dairy and dairy substitutes (71/390), closely followed by fruit and fruit juice (70/390). Overall, 31 advertisements referred to a specific disease, health problem, or risk factor and the most commonly mentioned were heart disease/heart-attack (12) cancer (seven) and diabetes (five). Majority of healthy eating messages currently advertised are by manufacturers, double that of retailers, with non-commercial sources representing only 2%. Processed foods were the most commonly advertised food form which contained a healthy eating message, this is of concern given the generally low nutritional value of these foods. Overall, there are a large number of advertisements in Australian magazines that contain healthy eating messages that may have the potential to communicate to consumers that there are health benefits associated with the consumption of certain foods. Future research to assess the accuracy of the information in such advertisements, and to examine consumer interpretations of these health message are important.

Review of the inhibition of biological activities of food-related selected toxins by natural compounds.

PubMed

Friedman, Mendel; Rasooly, Reuven

2013-04-23

There is a need to develop food-compatible conditions to alter the structures of fungal, bacterial, and plant toxins, thus transforming toxins to nontoxic molecules. The term 'chemical genetics' has been used to describe this approach. This overview attempts to survey and consolidate the widely scattered literature on the inhibition by natural compounds and plant extracts of the biological (toxicological) activity of the following food-related toxins: aflatoxin B1, fumonisins, and ochratoxin A produced by fungi; cholera toxin produced by Vibrio cholerae bacteria; Shiga toxins produced by E. coli bacteria; staphylococcal enterotoxins produced by Staphylococcus aureus bacteria; ricin produced by seeds of the castor plant Ricinus communis; and the glycoalkaloid α-chaconine synthesized in potato tubers and leaves. The reduction of biological activity has been achieved by one or more of the following approaches: inhibition of the release of the toxin into the environment, especially food; an alteration of the structural integrity of the toxin molecules; changes in the optimum microenvironment, especially pH, for toxin activity; and protection against adverse effects of the toxins in cells, animals, and humans (chemoprevention). The results show that food-compatible and safe compounds with anti-toxin properties can be used to reduce the toxic potential of these toxins. Practical applications and research needs are suggested that may further facilitate reducing the toxic burden of the diet. Researchers are challenged to (a) apply the available methods without adversely affecting the nutritional quality, safety, and sensory attributes of animal feed and human food and (b) educate food producers and processors and the public about available approaches to mitigating the undesirable effects of natural toxins that may present in the diet.

Review of the Inhibition of Biological Activities of Food-Related Selected Toxins by Natural Compounds

PubMed Central

Friedman, Mendel; Rasooly, Reuven

2013-01-01

There is a need to develop food-compatible conditions to alter the structures of fungal, bacterial, and plant toxins, thus transforming toxins to nontoxic molecules. The term ‘chemical genetics’ has been used to describe this approach. This overview attempts to survey and consolidate the widely scattered literature on the inhibition by natural compounds and plant extracts of the biological (toxicological) activity of the following food-related toxins: aflatoxin B1, fumonisins, and ochratoxin A produced by fungi; cholera toxin produced by Vibrio cholerae bacteria; Shiga toxins produced by E. coli bacteria; staphylococcal enterotoxins produced by Staphylococcus aureus bacteria; ricin produced by seeds of the castor plant Ricinus communis; and the glycoalkaloid α-chaconine synthesized in potato tubers and leaves. The reduction of biological activity has been achieved by one or more of the following approaches: inhibition of the release of the toxin into the environment, especially food; an alteration of the structural integrity of the toxin molecules; changes in the optimum microenvironment, especially pH, for toxin activity; and protection against adverse effects of the toxins in cells, animals, and humans (chemoprevention). The results show that food-compatible and safe compounds with anti-toxin properties can be used to reduce the toxic potential of these toxins. Practical applications and research needs are suggested that may further facilitate reducing the toxic burden of the diet. Researchers are challenged to (a) apply the available methods without adversely affecting the nutritional quality, safety, and sensory attributes of animal feed and human food and (b) educate food producers and processors and the public about available approaches to mitigating the undesirable effects of natural toxins that may present in the diet. PMID:23612750

Quantifying the biases in metagenome mining for realistic assessment of microbial ecology of naturally fermented foods.

PubMed

Keisam, Santosh; Romi, Wahengbam; Ahmed, Giasuddin; Jeyaram, Kumaraswamy

2016-09-27

Cultivation-independent investigation of microbial ecology is biased by the DNA extraction methods used. We aimed to quantify those biases by comparative analysis of the metagenome mined from four diverse naturally fermented foods (bamboo shoot, milk, fish, soybean) using eight different DNA extraction methods with different cell lysis principles. Our findings revealed that the enzymatic lysis yielded higher eubacterial and yeast metagenomic DNA from the food matrices compared to the widely used chemical and mechanical lysis principles. Further analysis of the bacterial community structure by Illumina MiSeq amplicon sequencing revealed a high recovery of lactic acid bacteria by the enzymatic lysis in all food types. However, Bacillaceae, Acetobacteraceae, Clostridiaceae and Proteobacteria were more abundantly recovered when mechanical and chemical lysis principles were applied. The biases generated due to the differential recovery of operational taxonomic units (OTUs) by different DNA extraction methods including DNA and PCR amplicons mix from different methods have been quantitatively demonstrated here. The different methods shared only 29.9-52.0% of the total OTUs recovered. Although similar comparative research has been performed on other ecological niches, this is the first in-depth investigation of quantifying the biases in metagenome mining from naturally fermented foods.

Food-Grade Synthesis of Maillard-Type Taste Enhancers Using Natural Deep Eutectic Solvents (NADES).

PubMed

Kranz, Maximilian; Hofmann, Thomas

2018-01-28

The increasing demand for healthier food products, with reduced levels of table salt, sugar, and mono sodium glutamate, reinforce the need for novel taste enhancers prepared by means of food-grade kitchen-type chemistry. Although several taste modulating compounds have been discovered in processed foods, their Maillard-type ex food production is usually not exploited by industrial process reactions as the yields of target compounds typically do not exceed 1-2%. Natural deep eutectic solvents (NADES) are reported for the first time to significantly increase the yields of the taste enhancers 1-deoxy-ᴅ-fructosyl-N-β-alanyl-ʟ-histidine (49% yield), N-(1-methyl-4-oxoimidazolidin-2-ylidene) aminopropionic acid (54% yield) and N²-(1-carboxyethyl) guanosine 5'-monophosphate (22% yield) at low temperature (80-100 °C) within a maximum reaction time of 2 h. Therefore, NADES open new avenues to a "next-generation culinary chemistry" overcoming the yield limitations of traditional Maillard chemistry approaches and enable a food-grade Maillard-type generation of flavor modulators.

Human milk: mother nature's prototypical probiotic food?

PubMed

McGuire, Michelle K; McGuire, Mark A

2015-01-01

The concept of "probiotic" is generally attributed to Dr. Ilya Mechnikov, who hypothesized that longevity could be enhanced by manipulating gastrointestinal microbes using naturally fermented foods. In 2001, a report of the FAO and WHO (2001 Oct, http://www.who.int/foodsafety/publications/fs_-management/en/probiotics.pdf) proposed a more restrictive definition of probiotic, as follows: "a live micro-organism which, when administered in adequate amounts, confers a health benefit on the host." As such, answering the fundamental question posed here-"Is human milk a probiotic?"-requires first grappling with the concept and meaning of the term probiotic. Nonetheless, one must also be convinced that human milk contains bacteria. Indeed, there are scores of publications providing evidence of a paradigm shift in this regard. Variation in the human-milk microbiome may be associated with maternal weight, mode of delivery, lactation state, gestation age, antibiotic use, and maternal health. Milk constituents (e.g., fatty acids and complex carbohydrates) might also be related to the abundance of specific bacterial taxa in milk. Whether these bacteria affect infant health is likely, but more studies are needed to test this hypothesis. In summary, a growing literature suggests that human milk, like all other fluids produced by the body, indeed contains viable bacteria. As such, and recognizing the extensive literature relating breastfeeding to optimal infant health, we propose that human milk should be considered a probiotic food. Determining factors that influence which bacteria are present in milk and if and how they influence the mother's and/or the recipient infant's health remain basic science and public health realms in which almost nothing is known. © 2015 American Society for Nutrition.

Biosynthesis and Function of Polyacetylenes and Allied Natural Products

PubMed Central

Minto, Robert E.; Blacklock, Brenda J.

2008-01-01

Polyacetylenic natural products are a substantial class of often unstable compounds containing a unique carbon-carbon triple bond functionality, that are intriguing for their wide variety of biochemical and ecological functions, economic potential, and surprising mode of biosynthesis. Isotopic tracer experiments between 1960 and 1990 demonstrated that the majority of these compounds are derived from fatty acid and polyketide precursors. During the past decade, research into the metabolism of polyacetylenes has swiftly advanced, driven by the cloning of the first genes responsible for polyacetylene biosynthesis in plants, moss, fungi, and actinomycetes, and the initial characterization of the gene products. The current state of knowledge of the biochemistry and molecular genetics of polyacetylenic secondary metabolic pathways will be presented together with an up-to-date survey of new terrestrial and marine natural products, their known biological activities, and a discussion of their likely metabolic origins. PMID:18387369

Red pepper (Capsicum annuum) carotenoids as a source of natural food colors: analysis and stability-a review.

PubMed

Arimboor, Ranjith; Natarajan, Ramesh Babu; Menon, K Ramakrishna; Chandrasekhar, Lekshmi P; Moorkoth, Vidya

2015-03-01

Carotenoids are increasingly drawing the attention of researchers as a major natural food color due to their inherent nutritional characteristics and the implicated possible role in prevention and protection against degenerative diseases. In this report, we review the role of red pepper as a source for natural carotenoids. The composition of the carotenoids in red pepper and the application of different methodologies for their analysis were discussed in this report. The stability of red pepper carotenoids during post-harvest processing and storage is also reviewed. This review highlights the potential of red pepper carotenoids as a source of natural food colors and also discusses the need for a standardized approach for the analysis and reporting of composition of carotenoids in plant products and designing model systems for stability studies.

Extraction methods and food uses of a natural red colorant from dye sorghum.

PubMed

Akogou, Folachodé Ug; Kayodé, Ap Polycarpe; den Besten, Heidy Mw; Linnemann, Anita R

2018-01-01

The interest in stable natural colorants for food applications continues to grow. A red pigment extracted from the leaf sheaths of a sorghum variety (Sorghum bicolor) with a high content of apigeninidin is widely used as a biocolorant in processed foods in West Africa. This study compared the colour and anthocyanin composition from traditional extraction methods to determine options for improvement and use of the red biocolorant from dye sorghum in the food sector. Sorghum biocolorant was commonly applied in fermented and heated foods. Traditional extraction methods predominantly differed in two aspects, namely the use of an alkaline rock salt (locally known as kanwu) and the temperature of the extraction water. Cool extraction using the alkaline ingredient was more efficient than hot alkaline and hot aqueous extractions in extracting anthocyanins. The apigeninidin content was three times higher in the cool and hot alkaline extracts than in the aqueous extract. Cool and hot alkaline extractions at pH 8-9 were the most efficient methods for extracting apigeninidin from dye sorghum leaf sheaths. Broader use of the sorghum biocolorant in foods requires further research on its effects on nutrient bioavailability and antioxidant activity. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Epoxide hydrolase-lasalocid a structure provides mechanistic insight into polyether natural product biosynthesis.

PubMed

Wong, Fong T; Hotta, Kinya; Chen, Xi; Fang, Minyi; Watanabe, Kenji; Kim, Chu-Young

2015-01-14

Biosynthesis of some polyether natural products involves a kinetically disfavored epoxide-opening cyclic ether formation, a reaction termed anti-Baldwin cyclization. One such example is the biosynthesis of lasalocid A, an ionophore antibiotic polyether. During lasalocid A biosynthesis, an epoxide hydrolase, Lsd19, converts the bisepoxy polyketide intermediate into the tetrahydrofuranyl-tetrahydropyran product. We report the crystal structure of Lsd19 in complex with lasalocid A. The structure unambiguously shows that the C-terminal domain of Lsd19 catalyzes the intriguing anti-Baldwin cyclization. We propose a general mechanism for epoxide selection by ionophore polyether epoxide hydrolases.

Mechanism and Stereochemistry of Polyketide Chain Elongation and Methyl Group Epimerization in Polyether Biosynthesis.

PubMed

Xie, Xinqiang; Garg, Ashish; Khosla, Chaitan; Cane, David E

2017-03-01

The polyketide synthases responsible for the biosynthesis of the polyether antibiotics nanchangmycin (1) and salinomycin (4) harbor a number of redox-inactive ketoreductase (KR 0 ) domains that are implicated in the generation of C2-epimerized (2S)-2-methyl-3-ketoacyl-ACP intermediates. Evidence that the natural substrate for the polyether KR 0 domains is, as predicted, a (2R)-2-methyl-3-ketoacyl-ACP intermediate, came from a newly developed coupled ketosynthase (KS)-ketoreductase (KR) assay that established that the decarboxylative condensation of methylmalonyl-CoA with S-propionyl-N-acetylcysteamine catalyzed by the Nan[KS1][AT1] didomain from module 1 of the nanchangmycin synthase generates exclusively the corresponding (2R)-2-methyl-3-ketopentanoyl-ACP (7a) product. In tandem equilibrium isotope exchange experiments, incubation of [2- 2 H]-(2R,3S)-2-methyl-3-hydroxypentanoyl-ACP (6a) with redox-active, epimerase-inactive EryKR6 from module 6 of the 6-deoxyerythronolide B synthase and catalytic quantities of NADP + in the presence of redox-inactive, recombinant NanKR1 0 or NanKR5 0 , from modules 1 and 5 of the nanchangmycin synthase, or recombinant SalKR7 0 from module 7 of the salinomycin synthase, resulted in first-order, time-dependent washout of deuterium from 6a. Control experiments confirmed that this washout was due to KR 0 -catalyzed isotope exchange of the reversibly generated, transiently formed oxidation product [2- 2 H]-(2R)-2-methyl-3-ketopentanoyl-ACP (7a), consistent with the proposed epimerase activity of each of the KR 0 domains. Although they belong to the superfamily of short chain dehydrogenase-reductases, the epimerase-active KR 0 domains from polyether synthases lack one or both residues of the conserved Tyr-Ser dyad that has previously been implicated in KR-catalyzed epimerizations.

Mechanism and Stereochemistry of Polyketide Chain Elongation and Methyl Group Epimerization in Polyether Biosynthesis

PubMed Central

Xie, Xinqiang; Garg, Ashish; Khosla, Chaitan; Cane, David E.

2017-01-01

The polyketide synthases responsible for the biosynthesis of the polyether antibiotics nanchangmycin (1) and salinomycin (4) harbor a number of redox-inactive ketoreductase (KR0) domains that are implicated in the generation of C2-epimerized (2S)-2-methyl-3-ketoacyl-ACP intermediates. Evidence that the natural substrate for the polyether KR0 domains is, as predicted, a (2R)-2-methyl-3-ketoacyl-ACP intermediate, came from a newly developed coupled ketosynthase (KS)-ketoreductase (KR) assay that established that the decarboxylative condensation of methylmalonyl-CoA with S-propionyl-N-acetylcysteamine catalyzed by the Nan[KS1][AT1] didomain from module 1 of the nanchangmycin synthase generates exclusively the corresponding (2R)-2-methyl-3-ketopentanoyl-ACP (7a) product. In tandem equilibrium isotope exchange experiments, incubation of [2-2H]-(2R,3S)-2-methyl-3-hydroxypentanoyl-ACP (6a) with redox-active, epimerase-inactive EryKR6 from module 6 of the 6-deoxyerythronolide B synthase and catalytic quantities of NADP+ in the presence of redox-inactive, recombinant NanKR10 or NanKR50, from modules 1 and 5 of the nanchangmycin synthase, or recombinant SalKR70 from module 7 of the salinomycin synthase, resulted in first-order, time-dependent washout of deuterium from 6a. Control experiments confirmed that this washout was due to KR0-catalyzed isotope exchange of the reversibly-generated, transiently-formed oxidation product [2-2H]-(2R)-2-methyl-3-ketopentanoyl-ACP (7a), consistent with the proposed epimerase activity of each of the KR0 domains. Although they belong to the superfamily of short chain dehydrogenase-reductases, the epimerase-active KR0 domains from polyether synthases lack one or both residues of the conserved Tyr-Ser dyad that has previously been implicated in KR-catalyzed epimerizations. PMID:28157306

Isolation and Assessment of the in Vitro Anti-Tumor Activity of Smenothiazole A and B, Chlorinated Thiazole-Containing Peptide/Polyketides from the Caribbean Sponge, Smenospongia aurea

PubMed Central

Esposito, Germana; Teta, Roberta; Miceli, Roberta; Ceccarelli, Luca S.; Della Sala, Gerardo; Camerlingo, Rosa; Irollo, Elena; Mangoni, Alfonso; Pirozzi, Giuseppe; Costantino, Valeria

2015-01-01

The study of the secondary metabolites contained in the organic extract of Caribbean sponge Smenospongia aurea led to the isolation of smenothiazole A (3) and B (4), hybrid peptide/polyketide compounds. Assays performed using four solid tumor cell lines showed that smenothiazoles exert a potent cytotoxic activity at nanomolar levels, with selectivity over ovarian cancer cells and a pro-apoptotic mechanism. PMID:25603342

Potential and attainable food production and food security in different regions

PubMed Central

Vries, F. W. T. Penning de; Rabbinge, R.; Groot, J. J. R.

1997-01-01

Growing prosperity in the South is accompanied by human diets that will claim more natural resources per capita. This reality, combined with growing populations, may raise the global demand for food crops two- to four-fold within two generations. Considering the large volume of natural resources and potential crop yields, it seems that this demand can be met smoothly. However, this is a fallacy for the following reasons. (i) Geographic regions differ widely in their potential food security: policy choices for agricultural use of natural resources are limited in Asia. For example, to ensure national self-sufficiency and food security, most of the suitable land (China) and nearly all of the surface water (India) are needed. Degradation restricts options further. (ii) The attainable level of agricultural production depends also on socio-economic conditions. Extensive poverty keeps the attainable food production too low to achieve food security, even when the yield gap is wide, as in Africa. (iii) Bio-energy, non-food crops and nature compete with food crops for natural resources. Global and regional food security are attainable, but only with major efforts. Strategies to achieve alternative aims will be discussed.

A coupled in vitro/in vivo approach for engineering a heterologous type III PKS to enhance polyketide biosynthesis in Saccharomyces cerevisiae.

PubMed

Vickery, Christopher R; Cardenas, Javier; Bowman, Marianne E; Burkart, Michael D; Da Silva, Nancy A; Noel, Joseph P

2018-06-01

Polyketides are attractive compounds for uses ranging from biorenewable chemical precursors to high-value therapeutics. In many cases, synthesis in a heterologous host is required to produce these compounds in industrially relevant quantities. The type III polyketide synthase 2-pyrone synthase (2-PS) from Gerbera hybrida was used for the production of triacetic acid lactone (TAL) in Saccharomyces cerevisiae. Initial in vitro characterization of 2-PS led to the identification of active site variants with improved kinetic properties relative to wildtype. Further in vivo evaluation in S. cerevisiae suggested certain 2-PS mutations altered enzyme stability during fermentation. In vivo experiments also revealed beneficial cysteine to serine mutations that were not initially explored due to their distance from the active site of 2-PS, leading to the design of additional 2-PS enzymes. While these variants showed varying catalytic efficiencies in vitro, they exhibited up to 2.5-fold increases in TAL production when expressed in S. cerevisiae. Coupling of the 2-PS variant [C35S,C372S] to an engineered S. cerevisiae strain led to over 10 g/L TAL at 38% of theoretical yield following fed-batch fermentation, the highest reported to date. Our studies demonstrate the success of a coupled in vitro/in vivo approach to engineering enzymes and provide insight on cysteine-rich enzymes and design principles toward their use in non-native microbial hosts. © 2018 Wiley Periodicals, Inc.

Phthalate exposure through food and consumers' risk perception of chemicals in food.

PubMed

Dickson-Spillmann, Maria; Siegrist, Michael; Keller, Carmen; Wormuth, Matthias

2009-08-01

Phthalates have been detected in various types of retail foods. Consumers' exposure to phthalates is common. Consumers are concerned about chemicals in food. Our aim was to investigate the relationships between consumers' exposure to phthalates through food, consumers' interest in a natural and healthy diet, risk perception of food chemicals, and consumers' diet patterns. We collected data through a mail survey in the adult Swiss-German population (N = 1,200). We modeled exposure to di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), and diethyl phthalate (DEP) based on a food frequency questionnaire and phthalate concentrations reported from food surveys. Using rating scales, we assessed risk perceptions of chemicals in food and interest in a natural and healthy diet. Higher risk perceptions and higher natural and healthy diet interest were associated with higher daily doses of DEHP, BBP, and DEP. No health risk from phthalates in food was identified for the vast majority of the population. Four consumers' diet clusters were discerned, with differences in phthalate exposure, risk perceptions, and interest in a natural and healthy diet. This study shows that even those consumers who express strong interest in natural food and low acceptance of food chemicals, and who try to make respective food choices, are exposed to contaminants such as phthalates.

Discovery Strategies of Bioactive Compounds Synthesized by Nonribosomal Peptide Synthetases and Type-I Polyketide Synthases Derived from Marine Microbiomes

PubMed Central

Amoutzias, Grigoris D.; Chaliotis, Anargyros; Mossialos, Dimitris

2016-01-01

Considering that 70% of our planet’s surface is covered by oceans, it is likely that undiscovered biodiversity is still enormous. A large portion of marine biodiversity consists of microbiomes. They are very attractive targets of bioprospecting because they are able to produce a vast repertoire of secondary metabolites in order to adapt in diverse environments. In many cases secondary metabolites of pharmaceutical and biotechnological interest such as nonribosomal peptides (NRPs) and polyketides (PKs) are synthesized by multimodular enzymes named nonribosomal peptide synthetases (NRPSes) and type-I polyketide synthases (PKSes-I), respectively. Novel findings regarding the mechanisms underlying NRPS and PKS evolution demonstrate how microorganisms could leverage their metabolic potential. Moreover, these findings could facilitate synthetic biology approaches leading to novel bioactive compounds. Ongoing advances in bioinformatics and next-generation sequencing (NGS) technologies are driving the discovery of NRPs and PKs derived from marine microbiomes mainly through two strategies: genome-mining and metagenomics. Microbial genomes are now sequenced at an unprecedented rate and this vast quantity of biological information can be analyzed through genome mining in order to identify gene clusters encoding NRPSes and PKSes of interest. On the other hand, metagenomics is a fast-growing research field which directly studies microbial genomes and their products present in marine environments using culture-independent approaches. The aim of this review is to examine recent developments regarding discovery strategies of bioactive compounds synthesized by NRPS and type-I PKS derived from marine microbiomes and to highlight the vast diversity of NRPSes and PKSes present in marine environments by giving examples of recently discovered bioactive compounds. PMID:27092515

Antifouling and antibacterial polyketides from marine gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023.

PubMed

Bao, Jie; Sun, Yu-Lin; Zhang, Xiao-Yong; Han, Zhuang; Gao, Hai-Chun; He, Fei; Qian, Pei-Yuan; Qi, Shu-Hua

2013-04-01

Two new polyketides, 6,8,5'6'-tetrahydroxy-3'-methylflavone (1) and paecilin C (2), together with six known analogs secalonic acid D (3), secalonic acid B (4) penicillixanthone A (5), emodin (6), citreorosein (7) and isorhodoptilometrin (8) were obtained from a broth of gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023. Compounds 1 and 6-8 had significant antifouling activity against Balanus amphitrite larvae settlement with EC50 values of 6.7, 6.1, 17.9 and 13.7 μg ml(-1), respectively, and 3-5 showed medium antibacterial activity against four tested bacterial strains. This was the first report of antibacterial activity of 3-5 against marine bacteria and antifouling activity of 6-8 against marine biofouling organism's larvae. The results indicated that gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023 strain could produce antifouling and antibacterial compounds that might aid the host gorgonian coral in protection against marine pathogen bacteria, biofouling organisms and other intruders.

The Prevalence and Natural History of Food Allergy.

PubMed

Kattan, Jacob

2016-07-01

Numerous studies have demonstrated that the prevalence of food allergy is increasing. Not only are more children being diagnosed with food allergies, but studies suggest that when people outgrow their food allergies, it is taking longer than was previously thought. Studies in recent years have noted factors that may lead to a lower likelihood of developing a food allergy, including the early introduction of common food allergens, having a sufficient vitamin D level, or having a higher maternal intake of peanut early in pregnancy. Given a recent report that sensitization to common food allergens did not increase from the late 1980s/early 1990s to the mid-2000s, further studies will need to examine if the rise in food allergy prevalence is due to a change in the relationship between sensitization and clinical allergy or changes in the recognition and diagnosis of food allergy.

Discovery and Characterization of a Group of Fungal Polycyclic Polyketide Prenyltransferases

PubMed Central

Chooi, Yit-Heng; Wang, Peng; Fang, Jinxu; Li, Yanran; Wu, Katherine; Wang, Pin; Tang, Yi

2014-01-01

The prenyltransferase (PTase) gene vrtC was proposed to be involved in viridicatumtoxin (1) biosynthesis in Penicillium aethiopicum. Targeted gene deletion and reconstitution of recombinant VrtC activity in vitro established that VrtC is a geranyl transferase that catalyzes a regiospecific Friedel-Crafts alkylation of the naphthacenedione carboxamide intermediate 2 at carbon 6 with geranyl diphosphate (GPP). VrtC can function in the absence of divalent ions and can utilize similar naphthacenedione substrates, such as the acetyl-primed TAN-1612 (4). Genome mining using the VrtC protein sequence leads to the identification of a homologous group of PTase genes in the genomes of human and animal-associated fungi. Three enzymes encoded by this new subgroup of PTase genes from Neosartorya fischeri, Microsporum canis and Trichophyton tonsurans were shown to be able to catalyze transfer of dimethylallyl to several tetracyclic naphthacenedione substrates in vitro. In total, seven C5- or C10-prenylated naphthacenedione compounds were generated. The regioselectivity of these new polycyclic PTases (pcPTases) was confirmed by characterization of product 9 obtained from biotransformation of 4 in Escherichia coli expressing the N. fischeri pcPTase gene. The discovery of this new subgroup of PTases extends our enzymatic tools for modifying polycyclic compounds and enables genome mining of new prenylated polyketides. PMID:22590971

Production and New Extraction Method of Polyketide Red Pigments Produced by Ascomycetous Fungi from Terrestrial and Marine Habitats

PubMed Central

Lebeau, Juliana; Venkatachalam, Mekala; Fouillaud, Mireille; Petit, Thomas; Vinale, Francesco; Dufossé, Laurent; Caro, Yanis

2017-01-01

The use of ascomycetous fungi as pigment producers opens the way to an alternative to synthetic dyes, especially in the red-dye industries, which have very few natural pigment alternatives. The present paper aimed to bio-prospect and screen out 15 selected ascomycetous fungal strains, originating from terrestrial and marine habitats belonging to seven different genera (Penicillium, Talaromyces, Fusarium, Aspergillus, Trichoderma, Dreschlera, and Paecilomyces). We identified four strains, Penicillium purpurogenum rubisclerotium, Fusarium oxysporum, marine strains identified as Talaromyces spp., and Trichoderma atroviride, as potential red pigment producers. The extraction of the pigments is a crucial step, whereby the qualitative and quantitative compositions of each fungal extract need to be respected for reliable identification, as well as preserving bioactivity. Furthermore, there is a growing demand for more sustainable and cost-effective extraction methods. Therefore, a pressurized liquid extraction technique was carried out in this study, allowing a greener and faster extraction step of the pigments, while preserving their chemical structures and bioactivities in comparison to conventional extraction processes. The protocol was illustrated with the production of pigment extracts from P. purpurogenum rubisclerotium and Talaromyces spp. Extracts were analyzed by high-performance liquid-chromatography combined with photodiode array-detection (HPLC-DAD) and high-resolution mass spectrometry (UHPLC-HRMS). The more promising strain was the isolate Talaromyces spp. of marine origin. The main polyketide pigment produced by this strain has been characterized as N-threoninerubropunctamine, a non-toxic red Monascus-like azaphilone pigment. PMID:29371552

Vitamin D toxicity of dietary origin in cats fed a natural complementary kitten food

PubMed Central

Crossley, Victoria J; Bovens, Catherine PV; Pineda, Carmen; Hibbert, Angie; Finch, Natalie C

2017-01-01

Case series summary This case series describes two young sibling cats and an additional unrelated cat, from two separate households, that developed hypercalcaemia associated with hypervitaminosis D. Excessive vitamin D concentrations were identified in a natural complementary tinned kitten food that was fed to all three cats as part of their diet. In one of the cases, there was clinical evidence of soft tissue mineralisation. The hypercalcaemia and soft tissue mineralisation resolved following withdrawal of the affected food and medical management of the hypercalcaemia. Relevance and novel information This case series demonstrates the importance of obtaining a thorough dietary history in patients presenting with hypercalcaemia and the measurement of vitamin D metabolites when investigating such cases. Complementary foods may have the potential to induce nutritional toxicity even when fed with complete, nutritionally balanced diets. PMID:29270305

Strain Prioritization and Genome Mining for Enediyne Natural Products

PubMed Central

Yan, Xiaohui; Ge, Huiming; Huang, Tingting; Hindra; Yang, Dong; Teng, Qihui; Crnovčić, Ivana; Li, Xiuling; Rudolf, Jeffrey D.; Lohman, Jeremy R.; Gansemans, Yannick; Zhu, Xiangcheng; Huang, Yong; Zhao, Li-Xing; Jiang, Yi; Van Nieuwerburgh, Filip; Rader, Christoph

2016-01-01

ABSTRACT The enediyne family of natural products has had a profound impact on modern chemistry, biology, and medicine, and yet only 11 enediynes have been structurally characterized to date. Here we report a genome survey of 3,400 actinomycetes, identifying 81 strains that harbor genes encoding the enediyne polyketide synthase cassettes that could be grouped into 28 distinct clades based on phylogenetic analysis. Genome sequencing of 31 representative strains confirmed that each clade harbors a distinct enediyne biosynthetic gene cluster. A genome neighborhood network allows prediction of new structural features and biosynthetic insights that could be exploited for enediyne discovery. We confirmed one clade as new C-1027 producers, with a significantly higher C-1027 titer than the original producer, and discovered a new family of enediyne natural products, the tiancimycins (TNMs), that exhibit potent cytotoxicity against a broad spectrum of cancer cell lines. Our results demonstrate the feasibility of rapid discovery of new enediynes from a large strain collection. PMID:27999165

Mining for Nonribosomal Peptide Synthetase and Polyketide Synthase Genes Revealed a High Level of Diversity in the Sphagnum Bog Metagenome

PubMed Central

Müller, Christina A.; Oberauner-Wappis, Lisa; Peyman, Armin; Amos, Gregory C. A.; Wellington, Elizabeth M. H.

2015-01-01

Sphagnum bog ecosystems are among the oldest vegetation forms harboring a specific microbial community and are known to produce an exceptionally wide variety of bioactive substances. Although the Sphagnum metagenome shows a rich secondary metabolism, the genes have not yet been explored. To analyze nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), the diversity of NRPS and PKS genes in Sphagnum-associated metagenomes was investigated by in silico data mining and sequence-based screening (PCR amplification of 9,500 fosmid clones). The in silico Illumina-based metagenomic approach resulted in the identification of 279 NRPSs and 346 PKSs, as well as 40 PKS-NRPS hybrid gene sequences. The occurrence of NRPS sequences was strongly dominated by the members of the Protebacteria phylum, especially by species of the Burkholderia genus, while PKS sequences were mainly affiliated with Actinobacteria. Thirteen novel NRPS-related sequences were identified by PCR amplification screening, displaying amino acid identities of 48% to 91% to annotated sequences of members of the phyla Proteobacteria, Actinobacteria, and Cyanobacteria. Some of the identified metagenomic clones showed the closest similarity to peptide synthases from Burkholderia or Lysobacter, which are emerging bacterial sources of as-yet-undescribed bioactive metabolites. This report highlights the role of the extreme natural ecosystems as a promising source for detection of secondary compounds and enzymes, serving as a source for biotechnological applications. PMID:26002894

Food-Derived Natural Compounds for Pain Relief in Neuropathic Pain.

PubMed

Lim, Eun Yeong; Kim, Yun Tai

2016-01-01

Neuropathic pain, defined as pain caused by a lesion or disease of the somatosensory nervous system, is characterized by dysesthesia, hyperalgesia, and allodynia. The number of patients with this type of pain has increased rapidly in recent years. Yet, available neuropathic pain medicines have undesired side effects, such as tolerance and physical dependence, and do not fully alleviate the pain. The mechanisms of neuropathic pain are still not fully understood. Injury causes inflammation and immune responses and changed expression and activity of receptors and ion channels in peripheral nerve terminals. Additionally, neuroinflammation is a known factor in the development and maintenance of neuropathic pain. During neuropathic pain development, the C-C motif chemokine receptor 2 (CCR2) acts as an important signaling mediator. Traditional plant treatments have been used throughout the world for treating diseases. We and others have identified food-derived compounds that alleviate neuropathic pain. Here, we review the natural compounds for neuropathic pain relief, their mechanisms of action, and the potential benefits of natural compounds with antagonistic effects on GPCRs, especially those containing CCR2, for neuropathic pain treatment.

Food colors: Existing and emerging food safety concerns.

PubMed

Oplatowska-Stachowiak, Michalina; Elliott, Christopher T

2017-02-11

Food colors are added to different types of commodities to increase their visual attractiveness or to compensate for natural color variations. The use of these additives is strictly regulated in the European Union, the United States, and many other countries worldwide. There is a growing concern about the safety of some commonly used legal food colorants and there is a trend to replace the synthetic forms with natural products. Additionally, a number of dyes with known or suspected genotoxic or carcinogenic properties have been shown to be added illegally to foods. Robust monitoring programs based on reliable detection methods are required to assure the food is free from harmful colors. The aim of this review is to present an up to date status of the various concerns arising from use of color additives in food. The most important food safety concerns in the field of food colors are lack of uniform regulation concerning legal food colors worldwide, possible link of artificial colors to hyperactive behavior, replacement of synthetic colors with natural ones, and the presence of harmful illegal dyes-both known but also new, emerging ones in food. The legal status of food color additives in the EU, United States, and worldwide is summarized. The reported negative health effects of both legal and illegal colors are presented. The European Rapid Alert System for Food and Feed notifications and US import alerts concerning food colors are analyzed and trends in fraudulent use of color additives identified. The detection methods for synthetic colors are also reviewed.

Food consumption patterns and economic growth. Increasing affluence and the use of natural resources.

PubMed

Gerbens-Leenes, P W; Nonhebel, S; Krol, M S

2010-12-01

This study analyzes relationships between food supply, consumption and income, taking supply, meat and dairy, and consumption composition (in macronutrients) as indicators, with annual per capita GDP as indicator for income. It compares food consumption patterns for 57 countries (2001) and gives time trends for western and southern Europe. Cross-sectional and time series relationships show similar patterns of change. For low income countries, GDP increase is accompanied by changes towards food consumption patterns with large gaps between supply and actual consumption. Total supply differs by a factor of two between low and high income countries. People in low income countries derive nutritional energy mainly from carbohydrates; the contribution of fats is small, that of protein the same as for high income countries and that of meat and dairy negligible. People in high income countries derive nutritional energy mainly from carbohydrates and fat, with substantial contribution of meat and dairy. Whenever and wherever economic growth occurs, food consumption shows similar change in direction. The European nutrition transition happened gradually, enabling agriculture and trade to keep pace with demand growth. Continuation of present economic trends might cause significant pressure on natural resources, because changes in food demand occur much faster than in the past, especially in Asia. Copyright © 2010 Elsevier Ltd. All rights reserved.

The Distant Siblings-A Phylogenomic Roadmap Illuminates the Origins of Extant Diversity in Fungal Aromatic Polyketide Biosynthesis.

PubMed

Koczyk, Grzegorz; Dawidziuk, Adam; Popiel, Delfina

2015-11-03

In recent years, the influx of newly sequenced fungal genomes has enabled sampling of secondary metabolite biosynthesis on an unprecedented scale. However, explanations of extant diversity which take into account both large-scale phylogeny reconstructions and knowledge gained from multiple genome projects are still lacking. We analyzed the evolutionary sources of genetic diversity in aromatic polyketide biosynthesis in over 100 model fungal genomes. By reconciling the history of over 400 nonreducing polyketide synthases (NR-PKSs) with corresponding species history, we demonstrate that extant fungal NR-PKSs are clades of distant siblings, originating from a burst of duplications in early Pezizomycotina and thinned by extensive losses. The capability of higher fungi to biosynthesize the simplest precursor molecule (orsellinic acid) is highlighted as an ancestral trait underlying biosynthesis of aromatic compounds. This base activity was modified during early evolution of filamentous fungi, toward divergent reaction schemes associated with biosynthesis of, for example, aflatoxins and fusarubins (C4-C9 cyclization) or various anthraquinone derivatives (C6-C11 cyclization). The functional plasticity is further shown to have been supplemented by modularization of domain architecture into discrete pieces (conserved splice junctions within product template domain), as well as tight linkage of key accessory enzyme families and divergence in employed transcriptional factors. Although the majority of discord between species and gene history is explained by ancient duplications, this landscape has been altered by more recent duplications, as well as multiple horizontal gene transfers. The 25 detected transfers include previously undescribed events leading to emergence of, for example, fusarubin biosynthesis in Fusarium genus. Both the underlying data and the results of present analysis (including alternative scenarios revealed by sampling multiple reconciliation optima) are

Paenilamicin: structure and biosynthesis of a hybrid nonribosomal peptide/polyketide antibiotic from the bee pathogen Paenibacillus larvae.

PubMed

Müller, Sebastian; Garcia-Gonzalez, Eva; Mainz, Andi; Hertlein, Gillian; Heid, Nina C; Mösker, Eva; van den Elst, Hans; Overkleeft, Herman S; Genersch, Elke; Süssmuth, Roderich D

2014-09-26

The spore-forming bacterium Paenibacillus larvae is the causative agent of American Foulbrood (AFB), a fatal disease of honey bees that occurs worldwide. Previously, we identified a complex hybrid nonribosomal peptide/polyketide synthesis (NRPS/PKS) gene cluster in the genome of P. larvae. Herein, we present the isolation and structure elucidation of the antibacterial and antifungal products of this gene cluster, termed paenilamicins. The unique structures of the paenilamicins give deep insight into the underlying complex hybrid NRPS/PKS biosynthetic machinery. Bee larval co-infection assays reveal that the paenilamicins are employed by P. larvae in fighting ecological niche competitors and are not directly involved in killing the bee larvae. Their antibacterial and antifungal activities qualify the paenilamicins as attractive candidates for drug development. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Natural Diversity in Heat Resistance of Bacteria and Bacterial Spores: Impact on Food Safety and Quality.

PubMed

den Besten, Heidy M W; Wells-Bennik, Marjon H J; Zwietering, Marcel H

2018-03-25

Heat treatments are widely used in food processing often with the aim of reducing or eliminating spoilage microorganisms and pathogens in food products. The efficacy of applying heat to control microorganisms is challenged by the natural diversity of microorganisms with respect to their heat robustness. This review gives an overview of the variations in heat resistances of various species and strains, describes modeling approaches to quantify heat robustness, and addresses the relevance and impact of the natural diversity of microorganisms when assessing heat inactivation. This comparison of heat resistances of microorganisms facilitates the evaluation of which (groups of) organisms might be troublesome in a production process in which heat treatment is critical to reducing the microbial contaminants, and also allows fine-tuning of the process parameters. Various sources of microbiological variability are discussed and compared for a range of species, including spore-forming and non-spore-forming pathogens and spoilage organisms. This benchmarking of variability factors gives crucial information about the most important factors that should be included in risk assessments to realistically predict heat inactivation of bacteria and spores as part of the measures for controlling shelf life and safety of food products.

The Insect Pathogen Serratia marcescens Db10 Uses a Hybrid Non-Ribosomal Peptide Synthetase-Polyketide Synthase to Produce the Antibiotic Althiomycin

PubMed Central

Challis, Gregory L.; Stanley-Wall, Nicola R.; Coulthurst, Sarah J.

2012-01-01

There is a continuing need to discover new bioactive natural products, such as antibiotics, in genetically-amenable micro-organisms. We observed that the enteric insect pathogen, Serratia marcescens Db10, produced a diffusible compound that inhibited the growth of Bacillis subtilis and Staphyloccocus aureus. Mapping the genetic locus required for this activity revealed a putative natural product biosynthetic gene cluster, further defined to a six-gene operon named alb1–alb6. Bioinformatic analysis of the proteins encoded by alb1–6 predicted a hybrid non-ribosomal peptide synthetase-polyketide synthase (NRPS-PKS) assembly line (Alb4/5/6), tailoring enzymes (Alb2/3) and an export/resistance protein (Alb1), and suggested that the machinery assembled althiomycin or a related molecule. Althiomycin is a ribosome-inhibiting antibiotic whose biosynthetic machinery had been elusive for decades. Chromatographic and spectroscopic analyses confirmed that wild type S. marcescens produced althiomycin and that production was eliminated on disruption of the alb gene cluster. Construction of mutants with in-frame deletions of specific alb genes demonstrated that Alb2–Alb5 were essential for althiomycin production, whereas Alb6 was required for maximal production of the antibiotic. A phosphopantetheinyl transferase enzyme required for althiomycin biosynthesis was also identified. Expression of Alb1, a predicted major facilitator superfamily efflux pump, conferred althiomycin resistance on another, sensitive, strain of S. marcescens. This is the first report of althiomycin production outside of the Myxobacteria or Streptomyces and paves the way for future exploitation of the biosynthetic machinery, since S. marcescens represents a convenient and tractable producing organism. PMID:23028578

Unhealthy food advertising directed to children on New Zealand television: extent, nature, impact and policy implications.

PubMed

Vandevijvere, Stefanie; Soupen, Alanna; Swinburn, Boyd

2017-12-01

To comprehensively assess the extent, nature and impact of unhealthy food advertising targeted to children on New Zealand television. Four weekdays and four weekend days were randomly selected over the period June-August 2015. Programming was recorded from 06.00 to 00.00 hours (midnight), for a total of 432 h. Audience ratings were used to identify children's peak viewing times. New Zealand. The three major free-to-air channels. The majority of foods advertised (n 1807) were unhealthy; 68·5 % of food advertisements included at least one food not permitted to be marketed to children according to the WHO nutrient profiling model. The mean hourly rate of unhealthy food advertising was 9·1 (sd 5·2). One-third of unhealthy food advertisements included a promotional character and one-third a premium offer. About 88 % of unhealthy food advertisements were shown during children's peak viewing times. If unhealthy food advertisements were to be restricted during times when at least 25 % of children are watching television, this would reduce the average unhealthy food advertising impact by 24 % during weekdays and 50 % during weekend days, and if the WHO instead of the current nutrient profiling model were used to restrict unhealthy food advertising to children, the average impact would be reduced by 24 % during weekdays and 29 % during weekend days. Current self-regulation is ineffective in protecting children from exposure to unhealthy food advertising on television. The WHO nutrient profiling model needs to be used to restrict unhealthy food advertising, especially during children's peak viewing times.

Aflatoxin control--how a regulatory agency managed risk from an unavoidable natural toxicant in food and feed.

PubMed

Park, D L; Stoloff, L

1989-04-01

The control by the Food and Drug Administration (FDA) of aflatoxin, a relatively recently discovered, unavoidable natural contaminant produced by specific molds that invade a number of basic food and feedstuffs, provides an example of the varying forces that affect risk assessment and management by a regulatory Agency. This is the story of how the FDA responded to the initial discovery of a potential carcinogenic hazard to humans in a domestic commodity, to the developing information concerning the nature of the hazard, to the economic and political pressures that are created by the impact of natural forces on regulatory controls, and to the restraints of laws within which the Agency must work. This story covers four periods: the years of discovery and action decisions on the basis of meager knowledge and the fear of cancer; the years of tinkering on paper with the regulatory process, the years of digestion of the accumulating knowledge, and the application of that knowledge to actions forced by natural events; and an audit of the current status of knowledge about the hazard from aflatoxin, and proposals for regulatory control based on that knowledge.

PRISM 3: expanded prediction of natural product chemical structures from microbial genomes

PubMed Central

Skinnider, Michael A.; Merwin, Nishanth J.; Johnston, Chad W.

2017-01-01

Abstract Microbial natural products represent a rich resource of pharmaceutically and industrially important compounds. Genome sequencing has revealed that the majority of natural products remain undiscovered, and computational methods to connect biosynthetic gene clusters to their corresponding natural products therefore have the potential to revitalize natural product discovery. Previously, we described PRediction Informatics for Secondary Metabolomes (PRISM), a combinatorial approach to chemical structure prediction for genetically encoded nonribosomal peptides and type I and II polyketides. Here, we present a ground-up rewrite of the PRISM structure prediction algorithm to derive prediction of natural products arising from non-modular biosynthetic paradigms. Within this new version, PRISM 3, natural product scaffolds are modeled as chemical graphs, permitting structure prediction for aminocoumarins, antimetabolites, bisindoles and phosphonate natural products, and building upon the addition of ribosomally synthesized and post-translationally modified peptides. Further, with the addition of cluster detection for 11 new cluster types, PRISM 3 expands to detect 22 distinct natural product cluster types. Other major modifications to PRISM include improved sequence input and ORF detection, user-friendliness and output. Distribution of PRISM 3 over a 300-core server grid improves the speed and capacity of the web application. PRISM 3 is available at http://magarveylab.ca/prism/. PMID:28460067

Using natural clinoptilolite zeolite as an amendment in vermicomposting of food waste.

PubMed

Zarrabi, Mansur; Mohammadi, Ali Akbar; Al-Musawi, Tariq J; Najafi Saleh, Hossein

2018-06-02

The effect of adding different proportions of natural clinoptilolite zeolite (5 and 10%) to food waste vermicomposting was investigated by assessing the physicochemical characteristics, worms' growth, and maturation time of finished vermicompost in comparison with the vermicompost prepared with no amendment (control). Vermicomposting was performed in 18 plastic containers for 70 days. The experimental results showed that the carbon-to-nitrogen (C/N) ratios were 15.85, 10.75, and 8.94 for 5 and 10% zeolite concentration and control after 70 days, respectively. The addition of zeolite could facilitate organic matter degradation and increase the total nitrogen content by adsorption of ammonium ions. Increasing the proportion of zeolite from 0% (control) to 10% decreased the ammonia escape by 25% in the final vermicompost. The natural zeolite significantly reduced the electrical conductivity (EC). At the end of the process, salinity uptake efficiency was 39.23% for 5% zeolite treatment and 45.23% for 10% zeolite treatment. The pH values at 5 and 10% zeolite-amended treatments were 7.31 and 7.57, respectively, in comparison to 7.10 in the control. The maturation time at the end of vermicomposting decreased with increasing zeolite concentration. The vermicompost containing 5 and 10% zeolite matured in 49 and 42 days, respectively, in comparison to 56 days for the control. With the use of an initial ten immature Eisenia fetida worms, the number of mature worms in the 10% zeolite treatment was 26 more than that in the 5% zeolite treatment (21 worms) and 9 more than that in the control treatment (17 worms). Significantly, natural zeolite showed a beneficial effect on the characteristics of the end-product when used in the vermicomposting of food waste.

Lexical-semantic deficits in processing food and non-food items.

PubMed

Rumiati, Raffaella I; Foroni, Francesco; Pergola, Giulio; Rossi, Paola; Silveri, Maria Caterina

2016-12-01

The study of category specific deficits in brain-damaged patients has been instrumental in explaining how knowledge about different types of objects is organized in the brain. Much of this research focused on testing putative semantic sensory/functional subsystems that could explain the observed dissociations in performance between living things (e.g., animals and fruits/vegetables) and non-living things (e.g., tools). As neuropsychological patterns that did not fit the original living/non-living distinction were observed, an alternative organization of semantic memory in domains constrained by evolutionary pressure was hypothesized. However, the category of food, that contains both living-natural items, such as an apple, and nonliving-manufactured items as in the case of a hamburger, has never been systematically investigated. As such, food category could turn out to be very useful to test whether the brain organizes the knowledge about food in sensory/functional subsystems, in a specific domain, or whether both approaches might need to be integrated. In the present study we tested the ability of patients with Alzheimer dementia (AD) and with Primary Progressive Aphasias (PPA) as well as healthy controls to perform a confrontation naming task, a categorization task, and a comprehension of edible (natural and manufactured food) and non edible items (tools and non-edible natural things) task (Tasks 1-3). The same photographs of natural and manufactured food were presented together with a description of food's sensory or functional property that could be either congruent or incongruent with that particular food (Task 4). Patients were overall less accurate than healthy individuals, and PPA patients were generally more impaired than AD patients, especially on the naming task. Food tended to be processed better than non-food in two out of three tasks (categorization and comprehension tasks). Patient groups showed no difference in naming food and non-food items, while

[Food prices in Brazil: prefer cooking to ultra-processed foods].

PubMed

Claro, Rafael Moreira; Maia, Emanuella Gomes; Costa, Bruna Vieira de Lima; Diniz, Danielle Pereira

2016-08-29

This study aims to describe the prices of food groups consumed in Brazil considering the nature, extent, and purpose of their processing. Data were obtained from the Brazilian Household Budget Survey for 2008-2009. The mean prices of the groups (natural, cooking ingredients, processed, and ultra-processed) and their respective food subgroups were estimated for Brazil according to income, region, and area. Natural products and cooking ingredients showed lower prices per calorie when compared to the other groups, suggesting an economic advantage to preparing meals at home when compared to replacing them with ultra-processed foods. Families with the highest income paid the highest prices for their food, while families in the Northeast and North regions and rural areas paid the lowest. While fresh foods (meat, milk, fruit, and vegetables) tend to cost more than ultra-processed foods, dry grains (like rice and beans) are a more economical alternative for adopting healthy eating practices.

Bioactive natural constituents from food sources-potential use in hypertension prevention and treatment.

PubMed

Huang, Wu-Yang; Davidge, Sandra T; Wu, Jianping

2013-01-01

Prevention and management of hypertension are the major public health challenges worldwide. Uncontrolled high blood pressure may lead to a shortened life expectancy and a higher morbidity due to a high risk of cardiovascular complications such as coronary heart disease (which leads to heart attack) and stroke, congestive heart failure, heart rhythm irregularities, and kidney failure etc. In recent years, it has been recognized that many dietary constituents may contribute to human cardiovascular health. There has been an increased focus on identifying these natural components of foods, describing their physiological activities and mechanisms of actions. Grain, vegetables, fruits, milk, cheese, meat, chicken, egg, fish, soybean, tea, wine, mushrooms, and lactic acid bacteria are various food sources with potential antihypertensive effects. Their main bioactive constituents include angiotensin I-converting enzyme (ACE) inhibitory peptides, vitamins C and E, flavonoids, flavanols, cathecins, anthocyanins, phenolic acids, polyphenols, tannins, resveratrol, polysaccharides, fiber, saponin, sterols, as well as K, Ca, and P. They may reduce blood pressure by different mechanisms, such as ACE inhibition effect, antioxidant, vasodilatory, opiate-like, Ca(2+) channel blocking, and chymase inhibitory activities. These functional foods may provide new therapeutic applications for hypertension prevention and treatment, and contribute to a healthy cardiovascular population. The present review summarizes the antihypertensive food sources and their bioactive constituents, as well as physiological mechanisms of dietary products, especially focusing on ACE inhibitory activity.

Study on the interaction of artificial and natural food colorants with human serum albumin: A computational point of view.

PubMed

Masone, Diego; Chanforan, Céline

2015-06-01

Due to the high amount of artificial food colorants present in infants' diets, their adverse effects have been of major concern among the literature. Artificial food colorants have been suggested to affect children's behavior, being hyperactivity the most common disorder. In this study we compare binding affinities of a group of artificial colorants (sunset yellow, quinoline yellow, carmoisine, allura red and tartrazine) and their natural industrial equivalents (carminic acid, curcumin, peonidin-3-glucoside, cyanidin-3-glucoside) to human serum albumin (HSA) by a docking approach and further refinement through atomistic molecular dynamics simulations. Due to the protein-ligand conformational interface complexity, we used collective variable driven molecular dynamics to refine docking predictions and to score them according to a hydrogen-bond criterion. With this protocol, we were able to rank ligand affinities to HSA and to compare between the studied natural and artificial food additives. Our results show that the five artificial colorants studied bind better to HSA than their equivalent natural options, in terms of their H-bonding network, supporting the hypothesis of their potential risk to human health. Copyright © 2015 Elsevier Ltd. All rights reserved.

Food-Derived Natural Compounds for Pain Relief in Neuropathic Pain

PubMed Central

Lim, Eun Yeong

2016-01-01

Neuropathic pain, defined as pain caused by a lesion or disease of the somatosensory nervous system, is characterized by dysesthesia, hyperalgesia, and allodynia. The number of patients with this type of pain has increased rapidly in recent years. Yet, available neuropathic pain medicines have undesired side effects, such as tolerance and physical dependence, and do not fully alleviate the pain. The mechanisms of neuropathic pain are still not fully understood. Injury causes inflammation and immune responses and changed expression and activity of receptors and ion channels in peripheral nerve terminals. Additionally, neuroinflammation is a known factor in the development and maintenance of neuropathic pain. During neuropathic pain development, the C-C motif chemokine receptor 2 (CCR2) acts as an important signaling mediator. Traditional plant treatments have been used throughout the world for treating diseases. We and others have identified food-derived compounds that alleviate neuropathic pain. Here, we review the natural compounds for neuropathic pain relief, their mechanisms of action, and the potential benefits of natural compounds with antagonistic effects on GPCRs, especially those containing CCR2, for neuropathic pain treatment. PMID:27891521

Estimate of the prevalence and burden of food poisoning by natural toxic compounds in South Korea.

PubMed

Park, Myoung Su; Bahk, Gyung Jin

2015-12-01

Many studies have attempted to accurately estimate the overall number of cases of foodborne illness, but there have not been many attempts to estimate the burden of foodborne disease caused by natural toxic compounds. This study estimated the number of cases due to specific natural toxins (seafood toxins, plant toxins, and mycotoxins) during 2008-2012 in South Korea, using data from the Health Insurance Review and Assessment Service (HIRA), while accounting for uncertainty in the estimate. The estimated annual occurrences of foodborne illness from natural toxic agents were 1088 (90% credible interval [CrI]: 883-1315), which suggests there are 21 times more cases than are reported, with 45.6% (n=496 [388-614]) and 54.4% (n=592 [423-790]), accounting for inpatient stays and outpatient visits, respectively. Among toxins, mushroom and plant toxins caused the highest illnesses, followed by toxic agents in seafood and mycotoxins. The 55-59year olds had the highest proportion of illnesses and those over the age of 40 accounted for 70.6% of all cases. The cases caused by mushroom poison, poisonous plants, and seafood toxins showed clear seasonal and regional differences. These results will be useful to food safety policymakers for the prevention and control of natural food poisons in South Korea. Copyright © 2015 Elsevier Ltd. All rights reserved.

Discriminating the reaction types of plant type III polyketide synthases

PubMed Central

Shimizu, Yugo; Ogata, Hiroyuki; Goto, Susumu

2017-01-01

Abstract Motivation: Functional prediction of paralogs is challenging in bioinformatics because of rapid functional diversification after gene duplication events combined with parallel acquisitions of similar functions by different paralogs. Plant type III polyketide synthases (PKSs), producing various secondary metabolites, represent a paralogous family that has undergone gene duplication and functional alteration. Currently, there is no computational method available for the functional prediction of type III PKSs. Results: We developed a plant type III PKS reaction predictor, pPAP, based on the recently proposed classification of type III PKSs. pPAP combines two kinds of similarity measures: one calculated by profile hidden Markov models (pHMMs) built from functionally and structurally important partial sequence regions, and the other based on mutual information between residue positions. pPAP targets PKSs acting on ring-type starter substrates, and classifies their functions into four reaction types. The pHMM approach discriminated two reaction types with high accuracy (97.5%, 39/40), but its accuracy decreased when discriminating three reaction types (87.8%, 43/49). When combined with a correlation-based approach, all 49 PKSs were correctly discriminated, and pPAP was still highly accurate (91.4%, 64/70) even after adding other reaction types. These results suggest pPAP, which is based on linear discriminant analyses of similarity measures, is effective for plant type III PKS function prediction. Availability and Implementation: pPAP is freely available at ftp://ftp.genome.jp/pub/tools/ppap/ Contact: goto@kuicr.kyoto-u.ac.jp Supplementary information: Supplementary data are available at Bioinformatics online. PMID:28334262

Trading off natural resources and rural livelihoods. A framework for sustainability assessment of small-scale food production in water-limited regions

NASA Astrophysics Data System (ADS)

Recanati, Francesca; Castelletti, Andrea; Dotelli, Giovanni; Melià, Paco

2017-12-01

Enhancing local production is key to promoting food security, especially in rural households of low-income countries, but may conflict with limited natural resources and ecosystems preservation. We propose a framework integrating the water-food nexus and a sustainable livelihoods perspective to assess small-scale food production in water-poor regions. We demonstrate it by assessing alternative production scenarios in the Gaza Strip at different spatial scales. At the scale of a single farm, there is a clear conflict among objectives: while cash crops ensure good incomes but contribute scarcely to domestic protein supply, crops performing well from the nutritional and environmental viewpoint are among the worst from the economic one. At the regional scale, domestic production might cover an important fraction of nutritional needs while contributing to household income, but water scarcity impairs the satisfaction of food demand by domestic production alone. Pursuing food security under multiple constraints thus requires a holistic perspective: we discuss how a multidimensional approach can promote the engagement of different stakeholders and allow the exploration of trade-offs between food security, sustainable exploitation of natural resources and economic viability.

The public understanding of nanotechnology in the food domain: the hidden role of views on science, technology, and nature.

PubMed

Vandermoere, Frederic; Blanchemanche, Sandrine; Bieberstein, Andrea; Marette, Stephan; Roosen, Jutta

2011-03-01

In spite of great expectations about the potential of nanotechnology, this study shows that people are rather ambiguous and pessimistic about nanotechnology applications in the food domain. Our findings are drawn from a survey of public perceptions about nanotechnology food and nanotechnology food packaging (N = 752). Multinomial logistic regression analyses further reveal that knowledge about food risks and nanotechnology significantly influences people's views about nanotechnology food packaging. However, knowledge variables were unrelated to support for nanofood, suggesting that an increase in people's knowledge might not be sufficient to bridge the gap between the excitement some business leaders in the food sector have and the restraint of the public. Additionally, opposition to nanofood was not related to the use of heuristics but to trust in governmental agencies. Furthermore, the results indicate that public perceptions of nanoscience in the food domain significantly relate to views on science, technology, and nature.

Naturally occurring and added sugar in relation to macronutrient intake and food consumption: results from a population-based study in adults.

PubMed

Kaartinen, Niina E; Similä, Minna E; Kanerva, Noora; Valsta, Liisa M; Harald, Kennet; Männistö, Satu

2017-01-01

Associations between sugar intake and the remaining diet are poorly described in modern food environments. We aimed at exploring associations of high naturally occurring and added sugar intakes with sociodemographic characteristics, intake of macronutrients, fibre and selected food groups. Our data comprised 4842 Finnish adults aged 25-74 years, who participated in the population-based DIetary, Lifestyle and Genetic determinants of Obesity and Metabolic syndrome (DILGOM) study. Diet was assessed by a validated 131-item FFQ. The food item disaggregation approach was used to estimate sucrose and fructose intakes from natural sources (naturally occurring sugar) and all other sources (added sugar). Sex-specific trends in macronutrient, fibre and food group intakes across sugar type quartiles were determined with general linear modelling adjusting for age, energy intake, leisure-time physical activity, smoking, education and BMI. Overall, results were similar across sexes. Young age was found to be a determinant of higher added sugar and lower naturally occurring sugar intakes ( P  < 0·0001). High added sugar intake was associated with low fibre intake ( P  < 0·0001) accompanied with lower fruit ( P < 0·0001 women; P  = 0·022 men) and vegetable consumption ( P  < 0·0001) and higher wheat consumption ( P  = 0·0003 women; P  < 0·0001 men). Opposite results were found for naturally occurring sugar. Butter consumption increased by 28-32 % ( P  < 0·0001) when shifting from the lowest to the highest added sugar intake quartile, while a decrease of 26-38 % ( P  < 0·0001) was found for naturally occurring sugar. Therefore, the associations of sugar types with dietary carbohydrate and fat quality seem opposing. Proper adjustments with dietary variables are needed when studying independent relationships between sugar and health.

Mining for Nonribosomal Peptide Synthetase and Polyketide Synthase Genes Revealed a High Level of Diversity in the Sphagnum Bog Metagenome.

PubMed

Müller, Christina A; Oberauner-Wappis, Lisa; Peyman, Armin; Amos, Gregory C A; Wellington, Elizabeth M H; Berg, Gabriele

2015-08-01

Sphagnum bog ecosystems are among the oldest vegetation forms harboring a specific microbial community and are known to produce an exceptionally wide variety of bioactive substances. Although the Sphagnum metagenome shows a rich secondary metabolism, the genes have not yet been explored. To analyze nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), the diversity of NRPS and PKS genes in Sphagnum-associated metagenomes was investigated by in silico data mining and sequence-based screening (PCR amplification of 9,500 fosmid clones). The in silico Illumina-based metagenomic approach resulted in the identification of 279 NRPSs and 346 PKSs, as well as 40 PKS-NRPS hybrid gene sequences. The occurrence of NRPS sequences was strongly dominated by the members of the Protebacteria phylum, especially by species of the Burkholderia genus, while PKS sequences were mainly affiliated with Actinobacteria. Thirteen novel NRPS-related sequences were identified by PCR amplification screening, displaying amino acid identities of 48% to 91% to annotated sequences of members of the phyla Proteobacteria, Actinobacteria, and Cyanobacteria. Some of the identified metagenomic clones showed the closest similarity to peptide synthases from Burkholderia or Lysobacter, which are emerging bacterial sources of as-yet-undescribed bioactive metabolites. This report highlights the role of the extreme natural ecosystems as a promising source for detection of secondary compounds and enzymes, serving as a source for biotechnological applications. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Phytosterol Profiles of Common Foods and Estimated Natural Intake of Different Structures and Forms in China.

PubMed

Wang, Mengmeng; Huang, Weisu; Hu, Yinzhou; Zhang, Liangxiao; Shao, Yafang; Wang, Meng; Zhang, Fang; Zhao, Ziyan; Mei, Xiaohong; Li, Tao; Wang, Donghui; Liang, Ying; Li, Jing; Huang, Yining; Zhang, Liuquan; Xu, Tao; Song, Huaxin; Zhong, Yongheng; Lu, Baiyi

2018-03-21

Phytosterols are well-known for their cholesterol-lowering effects, and the structures and forms of phytosterols affect their bioactivity. We aimed to illustrate the phytosterol profiles in common foods and estimate their natural intake in five geographical regions and among different age groups in China. In total, 12 phytosterols in free and esterified forms of 119 foods from five regions across China were examined using gas chromatography-mass spectrometry. Then, the dietary intake of phytosterols was calculated combined with the dietary foods intake data of Chinese people. The total phytosterol content was highest in vegetable oils (150.4-1230.9 mg/100 g), followed by legumes (129.6-275.6 mg/100 g), nuts (18.9-255.2 mg/100 g), and cereals (11.9-93.8 mg/100 g). Vegetables and fruits contained lower contents of total phytosterols. Phytosterols were mainly esterified in most common foods except in nuts. The predominant phytosterols were β-sitosterol, campesterol, and stigmasterol, all of which belonged to plant sterols and 4-desmethylsterols. Total phytosterol intake varied across different regions, ranging between 257.7 and 473.7 mg/standard-person (sp)/day, with the highest intake in Beijing, followed by Hangzhou, Wuhan, Chongqing, and Guangzhou. However, phytosterol proportion was similar across regions, with β-sitosterol accounting for 46.5-50.3% of the natural intake. Phytosterol intake was mainly constituted by plant sterols and 4-desmethylsterols in esterified form (61.9-74.6%). At the age of 2-70 years, phytosterol intake ranged from 154.3 mg/day to 348.0 mg/day in the national scale.

The role of natural galactagogues during breast feeding: focus on a Galega officinalis based food supplement.

PubMed

Salatino, Silvia; Giacomelli, Luca; Carnevali, Ilaria; Giacomelli, Erika

2017-12-01

Maternal milk is the optimal food for newborns. To this end, a number of interventions are used to enhance milk production. However, pharmacological interventions may be associated with a perceived risk of adverse effects and therefore many mothers prefer to rely on natural herbal remedies. Several herbal remedies have been traditionally used to this purpose. However, the level of evidence supporting their use is mixed. Among different currently-employed natural remedies, Galega officinalis has emerged to be one of those sustained by the strongest evidence. In this paper, we comment on a galega-based product. It is a standardized food supplement used to support breastfeeding mothers and to promote milk production containing Galega officinalis and other substances, including vitamins and magnesium, with potential effect on mother's well-being. In a recent product evaluation on a large sample of Italian women, the wide majority of mothers have declared to be satisfied with this product, and two third of them reported that the milk production was improved with the use of this product. Noteworthy, this galega-based food supplement was also reported to promote psychological benefit. The evidence of a perceived psychological benefit associated with this product is of particular importance, given the high degree of distress often experienced by mothers during the post-partum period. Last, a high level of safety was perceived by the participants. This galega-based food supplement does have a role in supporting breastfeeding mothers and enhance milk production during lactation. Further clinical trials could provide further evidence on the effectiveness of the product.

Perspective on the Ongoing Replacement of Artificial and Animal-Based Dyes with Alternative Natural Pigments in Foods and Beverages.

PubMed

Schweiggert, Ralf M

2018-03-28

This perspective highlights current trends, advances, and challenges related to the replacement of artificial dyes and the insect-based carmine with alternative natural pigments. Briefly reviewing the history of food coloration, key publications and public events leading to diverse concerns about artificial dyes and carmine will be summarized. An overview about promising alternatives in the market and those under development is provided, including a separate section on coloring foodstuffs. The perspective aims at supporting readers to keep abreast with the enormous efforts undertaken by the food and beverage industry to replace certain food dyes.

Modeling Sustainable Food Systems.

PubMed

Allen, Thomas; Prosperi, Paolo

2016-05-01

The processes underlying environmental, economic, and social unsustainability derive in part from the food system. Building sustainable food systems has become a predominating endeavor aiming to redirect our food systems and policies towards better-adjusted goals and improved societal welfare. Food systems are complex social-ecological systems involving multiple interactions between human and natural components. Policy needs to encourage public perception of humanity and nature as interdependent and interacting. The systemic nature of these interdependencies and interactions calls for systems approaches and integrated assessment tools. Identifying and modeling the intrinsic properties of the food system that will ensure its essential outcomes are maintained or enhanced over time and across generations, will help organizations and governmental institutions to track progress towards sustainability, and set policies that encourage positive transformations. This paper proposes a conceptual model that articulates crucial vulnerability and resilience factors to global environmental and socio-economic changes, postulating specific food and nutrition security issues as priority outcomes of food systems. By acknowledging the systemic nature of sustainability, this approach allows consideration of causal factor dynamics. In a stepwise approach, a logical application is schematized for three Mediterranean countries, namely Spain, France, and Italy.

Modeling Sustainable Food Systems

NASA Astrophysics Data System (ADS)

Allen, Thomas; Prosperi, Paolo

2016-05-01

The processes underlying environmental, economic, and social unsustainability derive in part from the food system. Building sustainable food systems has become a predominating endeavor aiming to redirect our food systems and policies towards better-adjusted goals and improved societal welfare. Food systems are complex social-ecological systems involving multiple interactions between human and natural components. Policy needs to encourage public perception of humanity and nature as interdependent and interacting. The systemic nature of these interdependencies and interactions calls for systems approaches and integrated assessment tools. Identifying and modeling the intrinsic properties of the food system that will ensure its essential outcomes are maintained or enhanced over time and across generations, will help organizations and governmental institutions to track progress towards sustainability, and set policies that encourage positive transformations. This paper proposes a conceptual model that articulates crucial vulnerability and resilience factors to global environmental and socio-economic changes, postulating specific food and nutrition security issues as priority outcomes of food systems. By acknowledging the systemic nature of sustainability, this approach allows consideration of causal factor dynamics. In a stepwise approach, a logical application is schematized for three Mediterranean countries, namely Spain, France, and Italy.

Genetic diversity and population structure of Lactobacillus delbrueckii subspecies bulgaricus isolated from naturally fermented dairy foods.

PubMed

Song, Yuqin; Sun, Zhihong; Guo, Chenyi; Wu, Yarong; Liu, Wenjun; Yu, Jie; Menghe, Bilige; Yang, Ruifu; Zhang, Heping

2016-03-04

Lactobacillus delbrueckii subsp. bulgaricus is one of the most widely used starter culture strains in industrial fermented dairy manufacture. It is also common in naturally fermented dairy foods made using traditional methods. The subsp. bulgaricus strains found in naturally fermented foods may be useful for improving current industrial starter cultures; however, little is known regarding its genetic diversity and population structure. Here, a collection of 298 L. delbrueckii strains from naturally fermented products in Mongolia, Russia, and West China was analyzed by multi-locus sequence typing based on eight conserved genes. The 251 confirmed subsp. bulgaricus strains produced 106 unique sequence types, the majority of which were assigned to five clonal complexes (CCs). The geographical distribution of CCs was uneven, with CC1 dominated by Mongolian and Russian isolates, and CC2-CC5 isolates exclusively from Xinjiang, China. Population structure analysis suggested six lineages, L1-L6, with various homologous recombination rates. Although L2-L5 were mainly restricted within specific regions, strains belonging to L1 and L6 were observed in diverse regions, suggesting historical transmission events. These results greatly enhance our knowledge of the population diversity of subsp. bulgaricus strains, and suggest that strains from CC1 and L4 may be useful as starter strains in industrial fermentation.

PRISM 3: expanded prediction of natural product chemical structures from microbial genomes.

PubMed

Skinnider, Michael A; Merwin, Nishanth J; Johnston, Chad W; Magarvey, Nathan A

2017-07-03

Microbial natural products represent a rich resource of pharmaceutically and industrially important compounds. Genome sequencing has revealed that the majority of natural products remain undiscovered, and computational methods to connect biosynthetic gene clusters to their corresponding natural products therefore have the potential to revitalize natural product discovery. Previously, we described PRediction Informatics for Secondary Metabolomes (PRISM), a combinatorial approach to chemical structure prediction for genetically encoded nonribosomal peptides and type I and II polyketides. Here, we present a ground-up rewrite of the PRISM structure prediction algorithm to derive prediction of natural products arising from non-modular biosynthetic paradigms. Within this new version, PRISM 3, natural product scaffolds are modeled as chemical graphs, permitting structure prediction for aminocoumarins, antimetabolites, bisindoles and phosphonate natural products, and building upon the addition of ribosomally synthesized and post-translationally modified peptides. Further, with the addition of cluster detection for 11 new cluster types, PRISM 3 expands to detect 22 distinct natural product cluster types. Other major modifications to PRISM include improved sequence input and ORF detection, user-friendliness and output. Distribution of PRISM 3 over a 300-core server grid improves the speed and capacity of the web application. PRISM 3 is available at http://magarveylab.ca/prism/. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Immunomodulatory Polyketides from a Phoma-like Fungus Isolated from a Soft Coral.

PubMed

Sun, Yi-Zhe; Kurtán, Tibor; Mándi, Attila; Tang, Hua; Chou, Yalan; Soong, Keryea; Su, Li; Sun, Peng; Zhuang, Chun-Lin; Zhang, Wen

2017-11-22

Fourteen new polyketides with a trans-fused decalin ring system, libertalides A-N (3-16), together with two known analogues, aspermytin A and its acetate (1, 2), were isolated from the fermentation extract of a coral-derived Libertasomyces sp. fungus. Their relative configurations were elucidated on the basis of detailed spectroscopic analysis, and the absolute configurations were determined by TDDFT-ECD and optical rotation (OR) calculations. The OR of 1 and 2 were found to have opposite signs in CH 3 CN and CHCl 3 , which was in agreement with the OR calculations producing alternating signs for the optical rotation depending on the applied conditions. Because the signs of the OR for 1 and 2 showed high solvent dependence, they may not be used alone to correlate the absolute configurations. Compound 16 displayed structural novelty characterized by an α-enol ether bridge conjugated with an aldehyde group. In in vitro immunomodulatory screening, compounds 1, 4, and 10 significantly induced the proliferation of CD3 + T cells, while compounds 2, 7, 11, and 14 significantly increased the CD4 + /CD8 + ratio at 3 μM. A preliminary structure-activity analysis revealed a crucial role of Δ 7 and a terminal OH group in the regulation of CD3 + T cell proliferation. This is the first report of immunoregulatory activity for metabolites of this kind.

Semi-quantitative assay for polyketide prymnesins isolated from Prymnesium parvum (Haptophyta) cultures.

PubMed

La Claire, J W; Manning, S R; Talarski, A E

2015-08-01

A fluorometric assay was developed to semi-quantify co-purified polyketide prymnesins-1 and -2 (PPs) from Prymnesium parvum cultures. Evaluations performed throughout the growth cycle of 5 practical salinity unit (PSU) cultures detected relatively 8-10 × more PPs in the culture medium (exotoxins) than in cells (endotoxins). The [exotoxin] remained stable and relatively low until post-log growth, when they increased significantly. However, on a per-cell basis, [exotoxin] declined throughout log phase and subsequently increased dramatically during late- and post-log phases. The [endotoxin] remained stable until late- and post-log phases, when it achieved its highest level before declining sharply. Shaking cultures of strains from Texas, South Carolina and the United Kingdom displayed dramatically different [exotoxin] during post-log decline. Cultures adapted to 30 PSU had significantly lower [exotoxin] over the course of cultivation than those grown at 5 PSU. Phosphate limitation enhanced [exotoxin] on a per-cell basis, especially in late- and post-log cultures. Media containing streptomycin exhibited a ∼20% increase in [exotoxin] in post-log cultures vs. control treatments, but it had only negligible effects on endotoxin levels. Brefeldin A had minimal effects on [exotoxin], suggesting that the presence of PPs in the medium may be largely derived from cell lysis or some other passive means. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigating the Biosynthesis of Natural Products from Marine Proteobacteria: A Survey of Molecules and Strategies

PubMed Central

Timmermans, Marshall L.; Paudel, Yagya P.; Ross, Avena C.

2017-01-01

The phylum proteobacteria contains a wide array of Gram-negative marine bacteria. With recent advances in genomic sequencing, genome analysis, and analytical chemistry techniques, a whole host of information is being revealed about the primary and secondary metabolism of marine proteobacteria. This has led to the discovery of a growing number of medically relevant natural products, including novel leads for the treatment of multidrug-resistant Staphylococcus aureus (MRSA) and cancer. Of equal interest, marine proteobacteria produce natural products whose structure and biosynthetic mechanisms differ from those of their terrestrial and actinobacterial counterparts. Notable features of secondary metabolites produced by marine proteobacteria include halogenation, sulfur-containing heterocycles, non-ribosomal peptides, and polyketides with unusual biosynthetic logic. As advances are made in the technology associated with functional genomics, such as computational sequence analysis, targeted DNA manipulation, and heterologous expression, it has become easier to probe the mechanisms for natural product biosynthesis. This review will focus on genomics driven approaches to understanding the biosynthetic mechanisms for natural products produced by marine proteobacteria. PMID:28762997

Investigating the Biosynthesis of Natural Products from Marine Proteobacteria: A Survey of Molecules and Strategies.

PubMed

Timmermans, Marshall L; Paudel, Yagya P; Ross, Avena C

2017-08-01

The phylum proteobacteria contains a wide array of Gram-negative marine bacteria. With recent advances in genomic sequencing, genome analysis, and analytical chemistry techniques, a whole host of information is being revealed about the primary and secondary metabolism of marine proteobacteria. This has led to the discovery of a growing number of medically relevant natural products, including novel leads for the treatment of multidrug-resistant Staphylococcus aureus (MRSA) and cancer. Of equal interest, marine proteobacteria produce natural products whose structure and biosynthetic mechanisms differ from those of their terrestrial and actinobacterial counterparts. Notable features of secondary metabolites produced by marine proteobacteria include halogenation, sulfur-containing heterocycles, non-ribosomal peptides, and polyketides with unusual biosynthetic logic. As advances are made in the technology associated with functional genomics, such as computational sequence analysis, targeted DNA manipulation, and heterologous expression, it has become easier to probe the mechanisms for natural product biosynthesis. This review will focus on genomics driven approaches to understanding the biosynthetic mechanisms for natural products produced by marine proteobacteria.

Identification of PaPKS1, a polyketide synthase involved in melanin formation and its use as a genetic tool in Podospora anserina.

PubMed

Coppin, Evelyne; Silar, Philippe

2007-08-01

In the filamentous fungus Podospora anserina, many pigmentation mutations map to the median region of the complex locus '14', called segment '29'. The data presented in this paper show that segment 29 corresponds to a gene encoding a polyketide synthase, designated PaPKS1, and identifies two mutations that completely or partially abolish the activity of the PaPKS1 polypeptide. We present evidence that the P. anserina green pigment is a (DHN)-melanin. Using the powerful genetic system of PaPKS1 cloning, we demonstrate that in P. anserina trans-duplicated sequences are subject to the RIP process as previously demonstrated for the cis-duplicated regions.

Cloning, sequencing, and analysis of the griseusin polyketide synthase gene cluster from Streptomyces griseus.

PubMed Central

Yu, T W; Bibb, M J; Revill, W P; Hopwood, D A

1994-01-01

A fragment of DNA was cloned from the Streptomyces griseus K-63 genome by using genes (act) for the actinorhodin polyketide synthase (PKS) of Streptomyces coelicolor as a probe. Sequencing of a 5.4-kb segment of the cloned DNA revealed a set of five gris open reading frames (ORFs), corresponding to the act PKS genes, in the following order: ORF1 for a ketosynthase, ORF2 for a chain length-determining factor, ORF3 for an acyl carrier protein, ORF5 for a ketoreductase, and ORF4 for a cyclase-dehydrase. Replacement of the gris genes with a marker gene in the S. griseus genome by using a single-stranded suicide vector propagated in Escherichia coli resulted in loss of the ability to produce griseusins A and B, showing that the five gris genes do indeed encode the type II griseusin PKS. These genes, encoding a PKS that is programmed differently from those for other aromatic PKSs so far available, will provide further valuable material for analysis of the programming mechanism by the construction and analysis of strains carrying hybrid PKS. Images PMID:8169211

Food Safety-Related Aspects of Parasites in Foods.

PubMed

Watthanakulpanich, Dorn

2015-01-01

As natural foods derive from soil or water environments, they may contain the infective stages of parasites endemic to these environments. Infective stages may enter the human food supply via infected animal hosts so there is a need for increased awareness of the impact of parasites on the food supply. Safe handling of food and good kitchen hygiene can prevent or reduce the risk posed by contaminated foodstuffs. In addition, parasites cannot cause a health problem in any thoroughly cooked foods.

Who was concerned about radiation, food safety, and natural disasters after the great East Japan earthquake and Fukushima catastrophe? A nationwide cross-sectional survey in 2012.

PubMed

Sugimoto, Takashi; Shinozaki, Tomohiro; Naruse, Takashi; Miyamoto, Yuki

2014-01-01

Disaster-related concerns by sub-populations have not been clarified after the great East Japan earthquake and the Fukushima nuclear power plant incidents. This paper assesses who was concerned about radiation, food safety, and natural disasters among the general population in order to buffer such concerns effectively. The hypothesis that women, parents, and family caregivers were most concerned about radiation, food safety, and natural disaster was tested using a varying-intercept multivariable logistic regression with 5809 responses from a nationwide cross-sectional survey random-sampled in March 2012. Many people were at least occasionally concerned about radiation (53.5%), food safety (47.3%), and about natural disaster (69.5%). Women were more concerned than men about radiation (OR = 1.67; 95% CI = 1.35-2.06), food safety (1.70; 1.38-2.10), and natural disasters (1.74; 1.39-2.19). Parents and family care needs were not significant. Married couples were more concerned about radiation (1.53; 1.33-1.77), food safety (1.38; 1.20-1.59), and natural disasters (1.30; 1.12-1.52). Age, child-cohabitation, college-completion, retirement status, homemaker status, and the house-damage certificate of the last disaster were also associated with at least one concern. Participants from the Kanto region were more concerned about radiation (2.08; 1.58-2.74) and food safety (1.30; 1.07-1.59), which demonstrate similar positive associations to participants from Tohoku where a disaster relief act was invoked (3.36; 2.25-5.01 about radiation, 1.49; 1.08-2.06 about food safety). Sectioning the populations by gender and other demographics will clarify prospective targets for interventions, allow for a better understanding of post-disaster concerns, and help communicate relevant information effectively.

Genetic diversity and population structure of Lactobacillus delbrueckii subspecies bulgaricus isolated from naturally fermented dairy foods

PubMed Central

Song, Yuqin; Sun, Zhihong; Guo, Chenyi; Wu, Yarong; Liu, Wenjun; Yu, Jie; Menghe, Bilige; Yang, Ruifu; Zhang, Heping

2016-01-01

Lactobacillus delbrueckii subsp. bulgaricus is one of the most widely used starter culture strains in industrial fermented dairy manufacture. It is also common in naturally fermented dairy foods made using traditional methods. The subsp. bulgaricus strains found in naturally fermented foods may be useful for improving current industrial starter cultures; however, little is known regarding its genetic diversity and population structure. Here, a collection of 298 L. delbrueckii strains from naturally fermented products in Mongolia, Russia, and West China was analyzed by multi-locus sequence typing based on eight conserved genes. The 251 confirmed subsp. bulgaricus strains produced 106 unique sequence types, the majority of which were assigned to five clonal complexes (CCs). The geographical distribution of CCs was uneven, with CC1 dominated by Mongolian and Russian isolates, and CC2–CC5 isolates exclusively from Xinjiang, China. Population structure analysis suggested six lineages, L1–L6, with various homologous recombination rates. Although L2–L5 were mainly restricted within specific regions, strains belonging to L1 and L6 were observed in diverse regions, suggesting historical transmission events. These results greatly enhance our knowledge of the population diversity of subsp. bulgaricus strains, and suggest that strains from CC1 and L4 may be useful as starter strains in industrial fermentation. PMID:26940047

Theme--Achieving 2020. Goal 3: All Students Are Conversationally Literate in Agriculture, Food, Fiber, and Natural Resource Systems.

ERIC Educational Resources Information Center

Trexler, Cary, Ed.

2000-01-01

Nine theme articles focus on the need for students to be conversationally literate about agriculture, food, fiber, and natural resources systems. Discusses the definition of conversational literacy, the human and institutional resources needed, and exemplary models for promoting literacy. (JOW)

"Everyone just ate good food": 'Good food' in Islamabad, Pakistan.

PubMed

Hasnain, Saher

2018-08-01

In recent years, consumption of alternatively produced foods has increased in popularity in response to the deleterious effects of rapidly globalising and industrialised food systems. Concerns over food safety in relation to these changes may result from elevated levels of risk and changing perceptions associated with food production practices. This paper explores how the middle class residents of Islamabad, Pakistan, use the concept of 'good food' to reconnect themselves with nature, changing food systems, and traditional values. The paper also demonstrates how these ideas relate to those of organic, local, and traditional food consumption as currently used in more economically developed states in the Global North. Through research based on participant observation and semi-structured interviews, this paper illustrates that besides price and convenience, purity, freshness, association with specific places, and 'Pakistani-ness' were considered as the basis for making decisions about 'good food'. The results show that while individuals are aware of and have some access to imported organic and local food, they prefer using holistic and culturally informed concepts of 'good food' instead that reconnect them with food systems. I argue that through conceptualisations of 'good food', the urban middle class in Islamabad is reducing their disconnection and dis-embeddedness from nature, the food systems, and their social identities. The paper contributes to literature on food anxieties, reconnections in food geography, and 'good food' perceptions, with a focus on Pakistan. Copyright © 2018. Published by Elsevier Ltd.

Genotoxicity evaluation of the naturally-derived food colorant, gardenia blue, and its precursor, genipin.

PubMed

Hobbs, Cheryl A; Koyanagi, Mihoko; Swartz, Carol; Davis, Jeffrey; Maronpot, Robert; Recio, Leslie; Hayashi, Shim-Mo

2018-06-04

Gardenia blue is widely used in Eastern Asia as a natural food colorant. To evaluate the genotoxic potential of gardenia blue, as well as genipin, the natural starting material from which it is produced, a GLP-compliant test battery was conducted according to OECD guidelines. No evidence of mutagenicity of gardenia blue was detected in a 5-strain bacterial reverse mutation assay, with or without metabolic activation; an equivocal response for genipin occurred in S. typhimurium TA97a without metabolic activation. In in vitro micronucleus and chromosome aberration assays, genipin tested positive under some test conditions; however, gardenia blue tested negative in both assays. In combined micronucleus/comet assays conducted in male and female B6C3F1 mice, exposure to genipin at doses reaching maximal toxicity (74 and 222 mg/kg bw/day for males and females, respectively) or gardenia blue tested up to the limit dose (2000 mg/kg bw/day) did not induce micronuclei in peripheral blood or DNA damage in several examined tissues. Modified ("reverse") comet assays showed no evidence of DNA crosslinking potential of either genipin, known to form crosslinks with other macromolecules, or gardenia blue. Our results indicate that consumption of gardenia blue in food products does not pose a significant genotoxic concern for humans. Copyright © 2018. Published by Elsevier Ltd.

21 CFR 582.30 - Natural substances used in conjunction with spices and other natural seasonings and flavorings.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Natural substances used in conjunction with spices and other natural seasonings and flavorings. 582.30 Section 582.30 Food and Drugs FOOD AND DRUG... SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Provisions § 582.30 Natural substances used in conjunction...

Integrating Disciplinary Core Ideas, the Agriculture, Food and Natural Resources Career Pathways and Next Generation Science Standards

ERIC Educational Resources Information Center

Kirby, Barrick R.; Heinert, Seth B.; Myers, Brian E.; Thoron, Andrew C.; Stofer, Kathryn

2018-01-01

The purpose of this study was to identify disciplinary core ideas that should be included in secondary school agriscience programs using a panel of experts in agricultural education, and to create a matrix of disciplinary core ideas, Agriculture, Food and Natural Resources career pathways performance indicators, and the Next Generation Science…

Filtered molasses concentrate from sugar cane: natural functional ingredient effective in lowering the glycaemic index and insulin response of high carbohydrate foods.

PubMed

Wright, Alison G; Ellis, Timothy P; Ilag, Leodevico L

2014-12-01

An aqueous filtered molasses concentrate (FMC) sourced from sugar cane was used as a functional ingredient in a range of carbohydrate-containing foods to reduce glycaemic response. When compared to untreated controls, postprandial glucose responses in the test products were reduced 5-20%, assessed by accredited glycaemic index (GI) testing. The reduction in glucose response in the test foods was dose-dependent and directly proportional to the ratio of FMC added to the amount of available carbohydrate in the test products. The insulin response to the foods was also reduced with FMC addition as compared to untreated controls. Inclusion of FMC in test foods did not replace any formulation ingredients; it was incorporated as an additional ingredient to existing formulations. Filtered molasses concentrate, made by a proprietary and patented process, contains many naturally occurring compounds. Some of the identified compounds are known to influence carbohydrate metabolism, and include phenolic compounds, minerals and organic acids. FMC, sourced from a by-product of sugar cane processing, shows potential as a natural functional ingredient capable of modifying carbohydrate metabolism and contributing to GI reduction of processed foods and beverages.

Applications of Nonenzymatic Catalysts to the Alteration of Natural Products.

PubMed

Shugrue, Christopher R; Miller, Scott J

2017-09-27

The application of small molecules as catalysts for the diversification of natural product scaffolds is reviewed. Specifically, principles that relate to the selectivity challenges intrinsic to complex molecular scaffolds are summarized. The synthesis of analogues of natural products by this approach is then described as a quintessential "late-stage functionalization" exercise wherein natural products serve as the lead scaffolds. Given the historical application of enzymatic catalysts to the site-selective alteration of complex molecules, the focus of this Review is on the recent studies of nonenzymatic catalysts. Reactions involving hydroxyl group derivatization with a variety of electrophilic reagents are discussed. C-H bond functionalizations that lead to oxidations, aminations, and halogenations are also presented. Several examples of site-selective olefin functionalizations and C-C bond formations are also included. Numerous classes of natural products have been subjected to these studies of site-selective alteration including polyketides, glycopeptides, terpenoids, macrolides, alkaloids, carbohydrates, and others. What emerges is a platform for chemical remodeling of naturally occurring scaffolds that targets virtually all known chemical functionalities and microenvironments. However, challenges for the design of very broad classes of catalysts, with even broader selectivity demands (e.g., stereoselectivity, functional group selectivity, and site-selectivity) persist. Yet, a significant spectrum of powerful, catalytic alterations of complex natural products now exists such that expansion of scope seems inevitable. Several instances of biological activity assays of remodeled natural product derivatives are also presented. These reports may foreshadow further interdisciplinary impacts for catalytic remodeling of natural products, including contributions to SAR development, mode of action studies, and eventually medicinal chemistry.

Growth, food consumption, and energy status of juvenile pallid sturgeon fed natural or artificial diets

USGS Publications Warehouse

Meyer, Hilary A.; Chipps, Steven R.; Graeb, Brian D. S.; Klumb, Robert A.

2016-01-01

Stocking of hatchery-raised fish is an important part of the pallid sturgeon Scaphirhynchus albus recovery program. In the wild, juvenile pallid sturgeon consume primarily aquatic insects, although little is known about specific dietary needs. In hatchery settings, pallid sturgeon are fed commercial diets that are formulated for salmonids. To compare food consumption, growth, and energy status of pallid sturgeon fed artificial or natural diets, we conducted a laboratory study using 24 juvenile pallid sturgeon (initial fork length 153–236 mm). Pallid sturgeon were fed a daily ration of either commercial pellets (1 mm, slow sinking; 45% protein, 19% fat) or chironomid larvae for 5 wk. Natural-fed pallid sturgeon exhibited a greater specific growth rate (2.12% d−1) than pellet-fed fish (0.06% d−1). Similarly, relative condition was greater for natural-fed sturgeon (Kn = 1.11) than that observed for pellet-fed fish (Kn = 0.87). In contrast, the hepatosomatic index was significantly higher in pellet-fed fish (2.5%), indicating a high lipid diet compared with natural-fed sturgeon (1.4%). Given the importance of natural diets to fish digestion and growth, it is suggested that a more holistic approach be applied in the development of a practical diet for pallid sturgeon that incorporates attributes of natural prey.

Ketide Synthase (KS) Domain Prediction and Analysis of Iterative Type II PKS Gene in Marine Sponge-Associated Actinobacteria Producing Biosurfactants and Antimicrobial Agents

PubMed Central

Selvin, Joseph; Sathiyanarayanan, Ganesan; Lipton, Anuj N.; Al-Dhabi, Naif Abdullah; Valan Arasu, Mariadhas; Kiran, George S.

2016-01-01

The important biological macromolecules, such as lipopeptide and glycolipid biosurfactant producing marine actinobacteria were analyzed and their potential linkage between type II polyketide synthase (PKS) genes was explored. A unique feature of type II PKS genes is their high amino acid (AA) sequence homology and conserved gene organization. These enzymes mediate the biosynthesis of polyketide natural products with enormous structural complexity and chemical nature by combinatorial use of various domains. Therefore, deciphering the order of AA sequence encoded by PKS domains tailored the chemical structure of polyketide analogs still remains a great challenge. The present work deals with an in vitro and in silico analysis of PKS type II genes from five actinobacterial species to correlate KS domain architecture and structural features. Our present analysis reveals the unique protein domain organization of iterative type II PKS and KS domain of marine actinobacteria. The findings of this study would have implications in metabolic pathway reconstruction and design of semi-synthetic genomes to achieve rational design of novel natural products. PMID:26903957

Water for wood products versus nature, food or feed

NASA Astrophysics Data System (ADS)

Schyns, Joep; Booij, Martijn; Hoekstra, Arjen

2017-04-01

more water available for the generation of other ecosystem services. Our findings contribute to a more complete picture of the human appropriation of water and the understanding of the interlinkages between the SDGs, thus feeding the debate on water for wood products versus nature, food or feed.

Geophysical Tools, Challenges and Perspectives Related to Natural Hazards, Climate Change and Food Security

NASA Astrophysics Data System (ADS)

Fucugauchi, J. U.

2013-05-01

In the coming decades a changing climate and natural hazards will likely increase the vulnerability of agricultural and other food production infrastructures, posing increasing treats to industrialized and developing economies. While food security concerns affect us globally, the huge differences among countries in stocks, population size, poverty levels, economy, technologic development, transportation, health care systems and basic infrastructure will pose a much larger burden on populations in the developing and less developed world. In these economies, increase in the magnitude, duration and frequency of droughts, floods, hurricanes, rising sea levels, heat waves, thunderstorms, freezing events and other phenomena will pose severe costs on the population. For this presentation, we concentrate on a geophysical perspective of the problems, tools available, challenges and short and long-term perspectives. In many instances, a range of natural hazards are considered as unforeseen catastrophes, which suddenly affect without warning, resulting in major losses. Although the forecasting capacity in the different situations arising from climate change and natural hazards is still limited, there are a range of tools available to assess scenarios and forecast models for developing and implementing better mitigation strategies and prevention programs. Earth observation systems, geophysical instrumental networks, satellite observatories, improved understanding of phenomena, expanded global and regional databases, geographic information systems, higher capacity for computer modeling, numerical simulations, etc provide a scientific-technical framework for developing strategies. Hazard prevention and mitigation programs will result in high costs globally, however major costs and challenges concentrate on the less developed economies already affected by poverty, famines, health problems, social inequalities, poor infrastructure, low life expectancy, high population growth

Polydiacetylene nanovesicles as carriers of natural phenylpropanoids for creating antimicrobial food-contact surfaces.

PubMed

Dogra, Navneet; Choudhary, Ruplal; Kohli, Punit; Haddock, John D; Makwana, Sanjaysinh; Horev, Batia; Vinokur, Yakov; Droby, Samir; Rodov, Victor

2015-03-11

The ultimate goal of this study was developing antimicrobial food-contact materials based on natural phenolic compounds using nanotechnological approaches. Among the methyl-β-cyclodextrin-encapsulated phenolics tested, curcumin showed by far the highest activity toward Escherichia coli with a minimum inhibitory concentration of 0.4 mM. Curcumin was enclosed in liposome-type polydiacetylene/phosholipid nanovesicles supplemented with N-hydroxysuccinimide and glucose. The fluorescence spectrum of the nanovesicles suggested that curcumin was located in their bilayer region. Free-suspended nanovesicles tended to bind to the bacterial surface and demonstrated bactericidal activity toward Gram-negative (E. coli) and vegetative cells of Gram-positive (Bacillus cereus) bacteria reducing their counts from 5 log CFU mL(-1) to an undetectable level within 8 h. The nanovesicles were covalently bound to silanized glass. Incubation of E. coli and B. cereus with nanovesicle-coated glass resulted in a 2.5 log reduction in their counts. After optimization this approach can be used for controlling microbial growth, cross-contamination, and biofilm formation on food-contacting surfaces.

Strategy for allergenicity assessment of 'natural novel foods': clinical and molecular investigation of exotic vegetables (water spinach, hyacinth bean and Ethiopian eggplant).

PubMed

Gubesch, M; Theler, B; Dutta, M; Baumer, B; Mathis, A; Holzhauser, T; Vieths, S; Ballmer-Weber, B K

2007-11-01

Foods not commonly consumed in the European Union must be proven safe before being brought to market, including an assessment of allergenicity. We present a three-stepwise strategy for allergenicity assessment of natural novel foods using three novel vegetables, namely, water spinach, hyacinth bean, Ethiopian eggplant. First, vegetable extracts were analyzed for the presence of pan-allergens [Bet v 1 homologous proteins, profilins, nonspecific lipid transfer proteins (LTP)] by immunoblot analysis with specific animal antibodies. Secondly, the IgE-binding of the food extracts was investigated by EAST (Enzyme-allergosorbent test) and immunoblot analysis using sera with IgE-reactivity to known pan-allergens or to phylogenetically related foods from subjects (i) allergic to birch, grass and mugwort pollen, (ii) with food allergy to soy, peanut, tomato, multiple pollen-related foods and (iii) sensitized to LTP. Thirdly, the clinical relevance of IgE-binding was assessed in vivo by skin prick testing (SPT) and open oral food challenges (OFC). Profilin and LTP were detected by animal antibodies in all vegetables, a Bet v 1 homologue selectively in hyacinth bean. IgE-binding to LTP, profilin and a Bet v 1 homologue was proven by immunoblot analysis and EAST. Positive SPT and OFC results were observed for all vegetables in pollen-allergic patients. Our stepwise procedure confirmed the presence and IgE-binding capacity of novel vegetable proteins homologous to known allergens in endemic vegetable foods. In vivo testing proved the potential of the novel vegetables to elicit clinical allergy. Hence, our described algorithm seems to be applicable for allergenicity testing of natural novel foods.

Modern 'junk food' and minimally-processed 'natural food' cafeteria diets alter the response to sweet taste but do not impair flavor-nutrient learning in rats.

PubMed

Palframan, Kristen M; Myers, Kevin P

2016-04-01

Animals learn to prefer and increase consumption of flavors paired with postingestive nutrient sensing. Analogous effects have been difficult to observe in human studies. One possibility is experience with the modern, processed diet impairs learning. Food processing manipulates flavor, texture, sweetness, and nutrition, obscuring ordinary correspondences between sensory cues and postingestive consequences. Over time, a diet of these processed 'junk' foods may impair flavor-nutrient learning. This 'flavor-confusion' hypothesis was tested by providing rats long-term exposure to cafeteria diets of unusual breadth (2 or 3 foods per day, 96 different foods over 3 months, plus ad libitum chow). One group was fed processed foods (PF) with added sugars/fats and manipulated flavors, to mimic the sensory-nutrient properties of the modern processed diet. Another group was fed only 'natural' foods (NF) meaning minimally-processed foods without manipulated flavors or added sugars/fats (e.g., fresh fruits, vegetables, whole grains) ostensibly preserving the ordinary correspondence between flavors and nutrition. A CON group was fed chow only. In subsequent tests of flavor-nutrient learning, PF and NF rats consistently acquired strong preferences for novel nutrient-paired flavors and PF rats exhibited enhanced learned acceptance, contradicting the 'flavor-confusion' hypothesis. An unexpected finding was PF and NF diets both caused lasting reduction in ad lib sweet solution intake. Groups did not differ in reinforcing value of sugar in a progressive ratio task. In lick microstructure analysis the NF group paradoxically showed increased sucrose palatability relative to PF and CON, suggesting the diets have different effects on sweet taste evaluation. Copyright © 2016 Elsevier Inc. All rights reserved.

An In Planta-Expressed Polyketide Synthase Produces (R)-Mellein in the Wheat Pathogen Parastagonospora nodorum

PubMed Central

Krill, Christian; Barrow, Russell A.; Chen, Shasha; Trengove, Robert; Oliver, Richard P.; Solomon, Peter S.

2014-01-01

Parastagonospora nodorum is a pathogen of wheat that affects yields globally. Previous transcriptional analysis identified a partially reducing polyketide synthase (PR-PKS) gene, SNOG_00477 (SN477), in P. nodorum that is highly upregulated during infection of wheat leaves. Disruption of the corresponding SN477 gene resulted in the loss of production of two compounds, which we identified as (R)-mellein and (R)-O-methylmellein. Using a Saccharomyces cerevisiae yeast heterologous expression system, we successfully demonstrated that SN477 is the only enzyme required for the production of (R)-mellein. This is the first identification of a fungal PKS that is responsible for the synthesis of (R)-mellein. The P. nodorum ΔSN477 mutant did not show any significant difference from the wild-type strain in its virulence against wheat. However, (R)-mellein at 200 μg/ml inhibited the germination of wheat (Triticum aestivum) and barrel medic (Medicago truncatula) seeds. Comparative sequence analysis identified the presence of mellein synthase (MLNS) homologues in several Dothideomycetes and two sodariomycete genera. Phylogenetic analysis suggests that the MLNSs in fungi and bacteria evolved convergently from fungal and bacterial 6-methylsalicylic acid synthases. PMID:25326302

Current Status and Future Prospects of Marine Natural Products (MNPs) as Antimicrobials

PubMed Central

Choudhary, Alka; Naughton, Lynn M.; Montánchez, Itxaso

2017-01-01

The marine environment is a rich source of chemically diverse, biologically active natural products, and serves as an invaluable resource in the ongoing search for novel antimicrobial compounds. Recent advances in extraction and isolation techniques, and in state-of-the-art technologies involved in organic synthesis and chemical structure elucidation, have accelerated the numbers of antimicrobial molecules originating from the ocean moving into clinical trials. The chemical diversity associated with these marine-derived molecules is immense, varying from simple linear peptides and fatty acids to complex alkaloids, terpenes and polyketides, etc. Such an array of structurally distinct molecules performs functionally diverse biological activities against many pathogenic bacteria and fungi, making marine-derived natural products valuable commodities, particularly in the current age of antimicrobial resistance. In this review, we have highlighted several marine-derived natural products (and their synthetic derivatives), which have gained recognition as effective antimicrobial agents over the past five years (2012–2017). These natural products have been categorized based on their chemical structures and the structure-activity mediated relationships of some of these bioactive molecules have been discussed. Finally, we have provided an insight into how genome mining efforts are likely to expedite the discovery of novel antimicrobial compounds. PMID:28846659

Current Status and Future Prospects of Marine Natural Products (MNPs) as Antimicrobials.

PubMed

Choudhary, Alka; Naughton, Lynn M; Montánchez, Itxaso; Dobson, Alan D W; Rai, Dilip K

2017-08-28

The marine environment is a rich source of chemically diverse, biologically active natural products, and serves as an invaluable resource in the ongoing search for novel antimicrobial compounds. Recent advances in extraction and isolation techniques, and in state-of-the-art technologies involved in organic synthesis and chemical structure elucidation, have accelerated the numbers of antimicrobial molecules originating from the ocean moving into clinical trials. The chemical diversity associated with these marine-derived molecules is immense, varying from simple linear peptides and fatty acids to complex alkaloids, terpenes and polyketides, etc. Such an array of structurally distinct molecules performs functionally diverse biological activities against many pathogenic bacteria and fungi, making marine-derived natural products valuable commodities, particularly in the current age of antimicrobial resistance. In this review, we have highlighted several marine-derived natural products (and their synthetic derivatives), which have gained recognition as effective antimicrobial agents over the past five years (2012-2017). These natural products have been categorized based on their chemical structures and the structure-activity mediated relationships of some of these bioactive molecules have been discussed. Finally, we have provided an insight into how genome mining efforts are likely to expedite the discovery of novel antimicrobial compounds.

Mixed deep learning and natural language processing method for fake-food image recognition and standardization to help automated dietary assessment.

PubMed

Mezgec, Simon; Eftimov, Tome; Bucher, Tamara; Koroušić Seljak, Barbara

2018-04-06

The present study tested the combination of an established and a validated food-choice research method (the 'fake food buffet') with a new food-matching technology to automate the data collection and analysis. The methodology combines fake-food image recognition using deep learning and food matching and standardization based on natural language processing. The former is specific because it uses a single deep learning network to perform both the segmentation and the classification at the pixel level of the image. To assess its performance, measures based on the standard pixel accuracy and Intersection over Union were applied. Food matching firstly describes each of the recognized food items in the image and then matches the food items with their compositional data, considering both their food names and their descriptors. The final accuracy of the deep learning model trained on fake-food images acquired by 124 study participants and providing fifty-five food classes was 92·18 %, while the food matching was performed with a classification accuracy of 93 %. The present findings are a step towards automating dietary assessment and food-choice research. The methodology outperforms other approaches in pixel accuracy, and since it is the first automatic solution for recognizing the images of fake foods, the results could be used as a baseline for possible future studies. As the approach enables a semi-automatic description of recognized food items (e.g. with respect to FoodEx2), these can be linked to any food composition database that applies the same classification and description system.

Characterization of household food insecurity in Québec: food and feelings.

PubMed

Hamelin, Anne-Marie; Beaudry, Micheline; Habicht, Jean-Pierre

2002-01-01

This study was undertaken to understand food insecurity from the perspective of households who experienced it. The results of group interviews and personal interviews with 98 low-income households from urban and rural areas in and around Québec City, Canada, elicited the meaning of "enough food" for the households and the range of manifestations of food insecurity. Two classes of manifestations characterized the experience of food insecurity: (1) its core characteristics: a lack of food encompassing the shortage of food, the unsuitability of both food and diet and a preoccupation with continuity in access to enough food; and a lack of control of households over their food situation; and (2) a related set of potential reactions: socio-familial perturbations, hunger and physical impairment, and psychological suffering. The results substantiate the existence of food insecurity among Québecers and confirm that the nature of this experience is consistent with many of the core components identified in upstate New York. This study underlines the monotony of the diet, describes the feeling of alienation, differentiates between a lack of food and the reactions that it engenders, and emphasizes the dynamic nature of the experience.

Healthy food trends -- microgreens

MedlinePlus

... medlineplus.gov/ency/patientinstructions/000730.htm Healthy food trends - microgreens To use the sharing features on this ... your local health food store or natural foods market. Look near the lettuce for packages of greens ...

Fruitflow®: the first European Food Safety Authority-approved natural cardio-protective functional ingredient.

PubMed

O'Kennedy, Niamh; Raederstorff, Daniel; Duttaroy, Asim K

2017-03-01

Hyperactive platelets, in addition to their roles in thrombosis, are also important mediators of atherogenesis. Antiplatelet drugs are not suitable for use where risk of a cardiovascular event is relatively low. It is therefore important to find alternative safe antiplatelet inhibitors for the vulnerable population who has hyperactive platelets in order to reduce the risk of cardiovascular disease. Potent antiplatelet factors were identified in water-soluble tomato extract (Fruitflow ® ), which significantly inhibited platelet aggregation. Human volunteer studies demonstrated the potency and bioavailability of active compounds in Fruitflow ® . Fruitflow ® became the first product in Europe to obtain an approved, proprietary health claim under Article 13(5) of the European Health Claims Regulation 1924/2006 on nutrition and health claims made on foods. Fruitflow ® is now commercially available in different countries worldwide. In addition to its reduction in platelet reactivity, Fruitflow ® contains anti-angiotensin-converting enzyme and anti-inflammatory factors, making it an effective and natural cardio-protective functional food.

Easing food waste could reduce pressure on natural resources

NASA Astrophysics Data System (ADS)

Showstack, Randy

2012-09-01

Calls to reduce food waste and enhance agricultural water efficiency were among the points raised during the 27 August opening session of World Water Week in Stockholm, Sweden. “More than one fourth of all the water we use worldwide is taken to grow over one billion tons of food that nobody eats. That water, together with the billions of dollars spent to grow, ship, package, and purchase the food, is sent down the drain,” said Torgny Holmgren, executive director of the Stockholm International Water Institute, which organizes World Water Week. “Reducing the waste of food is the smartest and most direct route to relieve pressure on water and land resources. It's an opportunity we cannot afford to overlook,” he added.

Food Safety, Food Fraud, and Food Defense: A Fast Evolving Literature.

PubMed

Manning, Louise; Soon, Jan Mei

2016-04-01

Intentional food crime is plural in nature in terms of the types of crime and the differing levels of financial gain. Successful models of food crime are dependent on how well the crime has been executed and at what point, or even if, detection actually occurs. The aim of this paper is to undertake a literature review and critique the often contradictory definitions that can be found in the literature in order to compare and contrast existing food crime risk assessment tools and their application. Food safety, food defense, and food fraud risk assessments consider different criteria in order to determine the degree of situational risk for each criteria and the measures that need to be implemented to mitigate that risk. Further research is required to support the development of global countermeasures, that are of value in reducing overall risk even when the potential hazards may be largely unknown, and specific countermeasures that can act against unique risks. © 2016 Institute of Food Technologists®

Child and adolescent fast-food choice and the influence of calorie labeling: a natural experiment.

PubMed

Elbel, B; Gyamfi, J; Kersh, R

2011-04-01

Obesity is an enormous public health problem and children have been particularly highlighted for intervention. Of notable concern is the fast-food consumption of children . However, we know very little about how children or their parents make fast-food choices, including how they respond to mandatory calorie labeling. We examined children's and adolescents' fast-food choice and the influence of calorie labels in low-income communities in New York City (NYC) and in a comparison city (Newark, NJ). Natural experiment: Survey and receipt data were collected from low-income areas in NYC, and Newark, NJ (as a comparison city), before and after mandatory labeling began in NYC. Study restaurants included four of the largest chains located in NYC and Newark: McDonald's, Burger King, Wendy's and Kentucky Fried Chicken. A total of 349 children and adolescents aged 1-17 years, who visited the restaurants with their parents (69%) or alone (31%) before or after labeling was introduced. In total, 90% were from racial or ethnic minority groups. We found no statistically significant differences in calories purchased before and after labeling; many adolescents reported noticing calorie labels after their introduction (57% in NYC) and a few considered the information when ordering (9%). Approximately 35% of adolescents ate fast food six or more times per week and 72% of adolescents reported that taste was the most important factor in their meal selection. Adolescents in our sample reported that parents have some influence on their meal selection. Adolescents in low-income communities notice calorie information at similar rates as adults, although they report being slightly less responsive to it than adults. We did not find evidence that labeling influenced adolescent food choice or parental food choices for children in this population.

Child and adolescent fast-food choice and the influence of calorie labeling: a natural experiment

PubMed Central

Elbel, B; Gyamfi, J; Kersh, R

2013-01-01

Objective Obesity is an enormous public health problem and children have been particularly highlighted for intervention. Of notable concern is the fast-food consumption of children. However, we know very little about how children or their parents make fast-food choices, including how they respond to mandatory calorie labeling. We examined children’s and adolescents’ fast-food choice and the influence of calorie labels in low-income communities in New York City (NYC) and in a comparison city (Newark, NJ). Design Natural experiment: Survey and receipt data were collected from low-income areas in NYC, and Newark, NJ (as a comparison city), before and after mandatory labeling began in NYC. Study restaurants included four of the largest chains located in NYC and Newark: McDonald’s, Burger King, Wendy’s and Kentucky Fried Chicken. Subjects A total of 349 children and adolescents aged 1–17 years who visited the restaurants with their parents (69%) or alone (31%) before or after labeling was introduced. In total, 90% were from racial or ethnic minority groups. Results We found no statistically significant differences in calories purchased before and after labeling; many adolescents reported noticing calorie labels after their introduction (57% in NYC) and a few considered the information when ordering (9%). Approximately 35% of adolescents ate fast food six or more times per week and 72% of adolescents reported that taste was the most important factor in their meal selection. Adolescents in our sample reported that parents have some influence on their meal selection. Conclusions Adolescents in low-income communities notice calorie information at similar rates as adults, although they report being slightly less responsive to it than adults. We did not find evidence that labeling influenced adolescent food choice or parental food choices for children in this population. PMID:21326209

Who Was Concerned about Radiation, Food Safety, and Natural Disasters after the Great East Japan Earthquake and Fukushima Catastrophe? A Nationwide Cross-Sectional Survey in 2012

PubMed Central

Sugimoto, Takashi; Shinozaki, Tomohiro; Naruse, Takashi; Miyamoto, Yuki

2014-01-01

Background Disaster-related concerns by sub-populations have not been clarified after the great East Japan earthquake and the Fukushima nuclear power plant incidents. This paper assesses who was concerned about radiation, food safety, and natural disasters among the general population in order to buffer such concerns effectively. Methods The hypothesis that women, parents, and family caregivers were most concerned about radiation, food safety, and natural disaster was tested using a varying-intercept multivariable logistic regression with 5809 responses from a nationwide cross-sectional survey random-sampled in March 2012. Results Many people were at least occasionally concerned about radiation (53.5%), food safety (47.3%), and about natural disaster (69.5%). Women were more concerned than men about radiation (OR = 1.67; 95% CI = 1.35–2.06), food safety (1.70; 1.38–2.10), and natural disasters (1.74; 1.39–2.19). Parents and family care needs were not significant. Married couples were more concerned about radiation (1.53; 1.33–1.77), food safety (1.38; 1.20–1.59), and natural disasters (1.30; 1.12–1.52). Age, child-cohabitation, college-completion, retirement status, homemaker status, and the house-damage certificate of the last disaster were also associated with at least one concern. Participants from the Kanto region were more concerned about radiation (2.08; 1.58–2.74) and food safety (1.30; 1.07–1.59), which demonstrate similar positive associations to participants from Tohoku where a disaster relief act was invoked (3.36; 2.25–5.01 about radiation, 1.49; 1.08–2.06 about food safety). Conclusions Sectioning the populations by gender and other demographics will clarify prospective targets for interventions, allow for a better understanding of post-disaster concerns, and help communicate relevant information effectively. PMID:25181292

Sex-dependent effects of larval food stress on adult performance under semi-natural conditions: only a matter of size?

PubMed

Rosa, Elena; Saastamoinen, Marjo

2017-07-01

Organisms with complex life-cycles acquire essential nutrients as juveniles, and hence even a short-term food stress during development can impose serious fitness costs apparent in adults. We used the Glanville fritillary butterfly to investigate the effects of larval food stress on adult performance under semi-natural conditions in a population enclosure. We were specifically interested in whether the negative effects observed were due to body mass reduction only or whether additional effects unrelated to pupal mass were evident. The two sexes responded differently to the larval food stress. In females, larval food stress reduced pupal mass and reproductive performance. The reduced reproductive performance was partially mediated by pupal mass reduction. Food stressed females also had reduced within-patch mobility, and this effect was not dependent on pupal mass. Conversely, food stress had no effect on male pupal mass, suggesting a full compensation via prolonged development time. Nonetheless, food stressed males were less likely to sire any eggs, potentially due to changes in their territorial behavior, as indicated by food stress also increasing male within-patch mobility (i.e., patrolling behavior). When males did sire eggs, the offspring number and viability were unaffected by male food stress treatment. Viability was in general higher for offspring sired by lighter males. Our study highlights how compensatory mechanisms after larval food stress can act in a sex-specific manner and that the alteration in body mass is only partially responsible for the reduced adult performance observed.

Evaluation of food protective property of five natural products using fresh-cut apple slice model.

PubMed

Hakkim, Faruk Lumanul; Mathiraj; Essa, Musthafa Mohamed; Arivazhagan, Girija; Guizani, Nejib; Hyuk, Song

2012-01-01

The present study evaluated the antioxidant (AA), antimicrobial and preservation effects of five plant derived natural products viz., Rosmarinic Acid (RA), p-Coumaric Acid (pCA), Trans-Cinnamic Acid (TCA), Hydroxyphenyllactic Acid (HPA) and Caffeic acid (CA) along with synthetic compounds (Ascorbic acid, gallic acid, citric acid and BHA) on fresh cut apple slices. Antimicrobial efficacy of these compounds against Bacillus licheniformis, Pseudomonas vulgaris, Shigella boydii, Salmonella typhi, Staphylococcus aureus, Listeria monocytogenes and Escherichia coli was found to be concentration dependent with the maximum inhibition observed at 500 microg mL(-1). A considerable AA potential of these compounds was observed in in vitro based assay system, with RA exhibiting significantly higher effect than the other compounds at 500 microg mL(-1). Furthermore the compounds at 500 microg mL(-1) significantly reduced the browning, maintained the acidic pH and restricted growth of L. monocytogenes even after 10 days of treatment. Ethanol accumulation in fresh cut apple slices increased significantly throughout the experimental period. Over all RA exhibited maximum effect in all the food preservation parameters studied suggesting that it has synchronized food protection effect and can be recommended as food additive.

Antimicrobial activities of natural antimicrobial compounds against susceptible and antibiotic-resistant pathogens in the absence and presence of food

USDA-ARS?s Scientific Manuscript database

In an effort to improve microbial food safety, we are studying the antimicrobial activities of different classes of natural compounds including plant essential oils, apple, grape, olive, and tea extracts, bioactive components, and seashell-derived chitosans against multiple foodborne pathogens in cu...

The natural food habits of grizzly bears in Yellowstone National Park, 1973-74

USGS Publications Warehouse

Mealey, Stephen Patrick

1980-01-01

 The natural food habits of grizzly bears (Ursus arctos horribilis Ord) in Yellowstone National Park were investigated in 1973-74 to identify the grizzly's energy sources and trophic level(s), nutrient use, and distribution. Food consumption was determined by scat analysis and field observations. Food quality and digestibility were estimated by chemical analysis. Grizzlies were distributed in 3 distinctive feeding economies: valley/plateau, a grass/rodent economy where grizzlies were intensive diggers; mountain, primarily a grass/springbeauty/root economy where grizzlies were casual diggers; and lake, primarily a fish/grass economy where grizzlies were fishers. The economies occured in areas with fertile soils; distribution of bears within each was related to the occurrence of succulent plants. The feeding cycle in the valley/plateau and mountain economies followed plant phenology. Grizzlies fed primarily on meat before green-up and on succulent herbs afterwards; meat, corms, berries, and nuts became important during the postgrowing season. Succulent grasses and sedges with an importance value percentage of 78.5 were the most important food items consumed. Protein from animal tissue was more digestible than protein from plant tissue. Storage fats were more digestible than structural fats. Food energy and digestibility were directly related. Five principle nutrient materials (listed with their percentage digestibilities) contributed to total energy intake: protein from succulent herbs, 42.8; protein and fat from animal material, 78.1; fat and protein from pine nuts, 73.6; starch, 78.8; and sugar from berries and fruits, digestibility undetermined. Protein from succulent herbs, with a nutritive value percentage of 77.3, was the grizzlies' primary energy source. Because succulent, preflowering herbs had higher protein levels than dry, mature herbs, grizzly use of succulent herbs guaranteed them the highest source of herbaceous protein. Low protein digestibility of

Capillary electrophoresis method for the discrimination between natural and artificial vanilla flavor for controlling food frauds.

PubMed

Lahouidak, Samah; Salghi, Rachid; Zougagh, Mohammed; Ríos, Angel

2018-03-06

A capillary electrophoresis method was developed for the determination of coumarin (COUM), ethyl vanillin (EVA), p-hydroxybenzaldehyde (PHB), p-hydroxybenzoic acid (PHBA), vanillin (VAN), vanillic acid (VANA) and vanillic alcohol (VOH) in vanilla products. The measured concentrations are compared to values obtained by liquid chromatography (LC) method. Analytical results, method precision, and accuracy data are presented and limits of detection for the method ranged from 2 to 5 μg/mL. The results obtained are used in monitoring the composition of vanilla flavorings, as well as for confirmation of natural or non-natural origin of vanilla in samples using four selected food samples containing this flavor. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Type II thioesterase gene (ECO-orf27) from Amycolatopsis orientalis influences production of the polyketide antibiotic, ECO-0501 (LW01).

PubMed

Shen, Yang; Huang, He; Zhu, Li; Luo, Minyu; Chen, Daijie

2012-11-01

ECO-orf27 associated with the cluster of ECO-0501 (LW01) from Amycolatopsis orientalis is deduced to encode a type II thioesterase. Disruption of ECO-orf27 reduced LW01 production by 95 %. Complementation of the disrupted mutant with intact ECO-orf27 restored the production of LW01 suggesting that ECO-orf27 is crucial for LW01 biosynthesis. ECO-TE I, the gene encoding type I thioesterase from LW01 polyketide synthases, cannot complement ECO-orf27 deficient mutant distinguishing ECO-orf27 from type I thioesterase gene. Type II thioesterase gene pikAV from Streptomyces venezuelae could complement ECO-orf27 in A. orientalis indicating that the two genes are equivalent in their function. Overexpression of ECO-orf27 resulted in a 20 % increase in LW01 production providing an alternative approach for yield improvement.

Linking secondary metabolites to biosynthesis genes in the fungal endophyte Cyanodermella asteris: The anti-cancer bisanthraquinone skyrin.

PubMed

Jahn, Linda; Schafhauser, Thomas; Wibberg, Daniel; Rückert, Christian; Winkler, Anika; Kulik, Andreas; Weber, Tilmann; Flor, Liane; van Pée, Karl-Heinz; Kalinowski, Jörn; Ludwig-Müller, Jutta; Wohlleben, Wolfgang

2017-09-10

Fungal aromatic polyketides display a very diverse and widespread group of natural products. Due to their excellent light absorption properties and widely studied biological activities, they offer numerous application for food, textile and pharmaceutical industry. The biosynthetic pathways of fungal aromatic polyketides usually involve a set of successive enzymes, in which a non-reductive polyketide synthase iteratively catalyzes the essential assembly of simple building blocks into (often polycyclic) aromatic compounds. However, only a limited number of such pathways have been described so far and further elucidation of the individual biosynthetic steps is needed to fully exploit the biotechnological and medicinal potential of these compounds. Here, we identified the bisanthraquinone skyrin as the main pigment of the fungus Cyanodermella asteris, an endophyte that has recently been isolated from the traditional Chinese medicinal plant Aster tataricus. The genome of C. asteris was sequenced, assembled and annotated, which enables first insights into a genome from a non-lichenized member of the class Lecanoromycetes. Genetic and in silico analyses led to the identification of a gene cluster of five genes suggested to encode the enzymatic pathway for skyrin. Our study is a starting point for rational pathway engineering in order to drive the production towards higher yields or more active derivatives. Moreover, our investigations revealed a large potential of secondary metabolite production in C. asteris as well as in all Lecanoromycetes of which genomes were available. These findings convincingly emphasize that Lecanoromycetes are prolific producers of secondary metabolites. Copyright © 2017 Elsevier B.V. All rights reserved.

Natural product diversity associated with the nematode symbionts Photorhabdus and Xenorhabdus

USDA-ARS?s Scientific Manuscript database

Xenorhabdus and Photorhabdus species produce many specialized metabolites derived from non-ribosomal synthetase (NRPS) or polyketide synthase (PKS) with utilities in maintaining a complex life cycle. Both bacteria undergo a symbiosis with nematodes which is then followed by an insect pathogenic phas...

Mood, food, and obesity

PubMed Central

Singh, Minati

2014-01-01

Food is a potent natural reward and food intake is a complex process. Reward and gratification associated with food consumption leads to dopamine (DA) production, which in turn activates reward and pleasure centers in the brain. An individual will repeatedly eat a particular food to experience this positive feeling of gratification. This type of repetitive behavior of food intake leads to the activation of brain reward pathways that eventually overrides other signals of satiety and hunger. Thus, a gratification habit through a favorable food leads to overeating and morbid obesity. Overeating and obesity stems from many biological factors engaging both central and peripheral systems in a bi-directional manner involving mood and emotions. Emotional eating and altered mood can also lead to altered food choice and intake leading to overeating and obesity. Research findings from human and animal studies support a two-way link between three concepts, mood, food, and obesity. The focus of this article is to provide an overview of complex nature of food intake where various biological factors link mood, food intake, and brain signaling that engages both peripheral and central nervous system signaling pathways in a bi-directional manner in obesity. PMID:25225489

Mood, food, and obesity.

PubMed

Singh, Minati

2014-01-01

Food is a potent natural reward and food intake is a complex process. Reward and gratification associated with food consumption leads to dopamine (DA) production, which in turn activates reward and pleasure centers in the brain. An individual will repeatedly eat a particular food to experience this positive feeling of gratification. This type of repetitive behavior of food intake leads to the activation of brain reward pathways that eventually overrides other signals of satiety and hunger. Thus, a gratification habit through a favorable food leads to overeating and morbid obesity. Overeating and obesity stems from many biological factors engaging both central and peripheral systems in a bi-directional manner involving mood and emotions. Emotional eating and altered mood can also lead to altered food choice and intake leading to overeating and obesity. Research findings from human and animal studies support a two-way link between three concepts, mood, food, and obesity. The focus of this article is to provide an overview of complex nature of food intake where various biological factors link mood, food intake, and brain signaling that engages both peripheral and central nervous system signaling pathways in a bi-directional manner in obesity.

An Sfp-type PPTase and associated polyketide and nonribosomal peptide synthases in Agrobacterium vitis are essential for induction of tobacco hypersensitive response and grape necrosis.

PubMed

Zheng, Desen; Burr, Thomas J

2013-07-01

An Sfp-type phosphopantetheinyl transferase (PPTase) encoding gene F-avi5813 in Agrobacterium vitis F2/5 was found to be required for the induction of a tobacco hypersensitive response (HR) and grape necrosis. Sfp-type PPTases are post-translation modification enzymes that activate acyl-carry protein (ACP) domains in polyketide synthases (PKS) and peptidyl-carrier protein (PCP) domains of nonribosomal peptide synthases (NRPS). Mutagenesis of PKS and NRPS genes in A. vitis led to the identification of a PKS gene (F-avi4330) and NRPS gene (F-avi3342) that are both required for HR and necrosis. The gene immediately downstream of F-avi4330 (F-avi4329) encoding a predicted aminotransferase was also found to be required for HR and necrosis. Regulation of F-avi4330 and F-avi3342 by quorum-sensing genes avhR, aviR, and avsR and by a lysR-type regulator, lhnR, was investigated. It was determined that F-avi4330 expression is positively regulated by avhR, aviR, and lhnR and negatively regulated by avsR. F-avi3342 was found to be positively regulated by avhR, aviR, and avsR and negatively regulated by lhnR. Our results suggest that a putative hybrid peptide-polyketide metabolite synthesized by F-avi4330 and F-avi3342 is associated with induction of tobacco HR and grape necrosis. This is the first report that demonstrates that NRPS and PKS play essential roles in conferring the unique ability of A. vitis to elicit a non-host-specific HR and host-specific necrosis.

Female offspring desertion and male-only care increase with natural and experimental increase in food abundance

PubMed Central

Eldegard, Katrine; Sonerud, Geir A.

2009-01-01

In species with biparental care, one parent may escape the costs of parental care by deserting and leaving the partner to care for the offspring alone. A number of theoretical papers have suggested a link between uniparental offspring desertion and ecological factors, but empirical evidence is scarce. We investigated the relationship between uniparental desertion and food abundance in a natural population of Tengmalm's owl Aegolius funereus, both by means of a 5-year observational study and a 1-year experimental study. Parents and offspring were fitted with radio-transmitters in order to reveal the parental care strategy (i.e. care or desert) of individual parents, and to keep track of the broods post-fledging. We found that 70 per cent of the females from non-experimental nests deserted, while their partner continued to care for their joint offspring alone. Desertion rate was positively related to natural prey population densities and body reserves of the male partner. In response to food supplementation, a larger proportion of the females deserted, and females deserted the offspring at an earlier age. Offspring survival during the post-fledging period tended to be lower in deserted than in non-deserted broods. We argue that the most important benefit of deserting may be remating (sequential polyandry). PMID:19324835

Female offspring desertion and male-only care increase with natural and experimental increase in food abundance.

PubMed

Eldegard, Katrine; Sonerud, Geir A

2009-05-07

In species with biparental care, one parent may escape the costs of parental care by deserting and leaving the partner to care for the offspring alone. A number of theoretical papers have suggested a link between uniparental offspring desertion and ecological factors, but empirical evidence is scarce. We investigated the relationship between uniparental desertion and food abundance in a natural population of Tengmalm's owl Aegolius funereus, both by means of a 5-year observational study and a 1-year experimental study. Parents and offspring were fitted with radio-transmitters in order to reveal the parental care strategy (i.e. care or desert) of individual parents, and to keep track of the broods post-fledging. We found that 70 per cent of the females from non-experimental nests deserted, while their partner continued to care for their joint offspring alone. Desertion rate was positively related to natural prey population densities and body reserves of the male partner. In response to food supplementation, a larger proportion of the females deserted, and females deserted the offspring at an earlier age. Offspring survival during the post-fledging period tended to be lower in deserted than in non-deserted broods. We argue that the most important benefit of deserting may be remating (sequential polyandry).

Summer co-existence of small-sized cyprinid and percid individuals in natural and impounded stretches of a lowland river: food niche partitioning among fishes.

PubMed

Lik, J; Dukowska, M; Grzybkowska, M; Leszczyńska, J

2017-04-01

Due to changes of discharge regime downstream of a dam reservoir, an alluvial natural stretch of the Warta River changed to a macrophyte-dominated ecosystem. Large patches of submersed, aquatic macrophytes appeared in summer and their effect is analysed in this study. These patches contained enriched macroinvertebrate assemblages (epiphyton and benthos) and they were refuge for both zooplankton and young fishes released from the reservoir. Despite these altered conditions in this stretch, roach Rutilus rutilus, perch Perca fluviatilis and ruffe Gymnocephalus cernua dominated, as they did in the natural backwater. Fishes were sampled every 2 weeks from June to August, together with their food resources to assess the partitioning of the diet among small individuals of the three species in both stretches (the natural and affected ones). The aim of the analysis was to answer how animal food associated with water plants was partitioned between the species. In both stretches, G. cernua were primarily benthivorous, but epiphytic fauna, zooplankton and large-sized benthic chironomid larvae replaced lack of many large, benthic insects in the tailwater. Levins' food breath index decreased from 0·36 in the backwater to 0·29 in the tailwater. An opposite trend was observed for P. fluviatilis occurring among macrophytes. Perca fluviatilis were competitors of R. rutilus and took food not only in or on the river bed, but also in the water column. They ate zooplankton and epiphytic fauna and Levins' index increased from 0·32 to 0·44 in the tailwater. Rutilus rutilus fed on adult insects, algae and plant fragments in the natural stretch. In the tailwater, these food types were chiefly complemented by zooplankton. Despite this, the niche breadth of R. rutilus was similar at the two sites. Abundance of food associated with the macrophytes appeared to facilitate cohabitation in the abundant fish populations, but P. fluviatilis appeared to benefit the most in the altered river

Food and beverage price discounts to improve health in remote Aboriginal communities: mixed method evaluation of a natural experiment.

PubMed

Ferguson, Megan; O'Dea, Kerin; Holden, Stacey; Miles, Eddie; Brimblecombe, Julie

2017-02-01

Retrospectively evaluate food price discounts in remote Aboriginal community stores. Four price discount strategies of 10% were designed in 2010, aiming to influence grocery, fruit, vegetables and diet soft-drink sales. This natural experiment across a group of stores was evaluated using an explanatory, sequential mixed method design through analysis of store point-of-sale, document, observation and interview data. The outcome was measured by change in: 1) percentage of grocery sales to total food and beverage; 2) fruit and vegetable sales; and 3) diet soft-drink sales. Qualitative data enabled the interpretation of outcomes through understanding perceived success and benefits, and enablers and barriers to implementation. Eighteen community stores and 54 informants participated. While targeted price discounts were considered important to improving health, no discernible effect was evident, due to inadequate design and communication of discount promotion, and probably inadequate magnitude of discount. Strategy impact on food and beverage sales was limited by promotion and magnitude of discount. Implication for Public Health: This study demonstrates key factors and commitment required to design, communicate, implement and monitor strategies to improve health in this challenging remote retail context. Evaluation of natural experiments can contribute evidence to policy-making. © 2016 The Authors.

Organohalogen Compounds in Pet Dog and Cat: Do Pets Biotransform Natural Brominated Products in Food to Harmful Hydroxlated Substances?

PubMed

Mizukawa, Hazuki; Nomiyama, Kei; Nakatsu, Susumu; Iwata, Hisato; Yoo, Jean; Kubota, Akira; Yamamoto, Miyuki; Ishizuka, Mayumi; Ikenaka, Yoshinori; Nakayama, Shouta M M; Kunisue, Tatsuya; Tanabe, Shinsuke

2016-01-05

There are growing concerns about the increase in hyperthyroidism in pet cats due to exposure to organohalogen contaminants and their hydroxylated metabolites. This study investigated the blood contaminants polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated derivatives (OH-PCBs, OH-PBDEs, and MeO-PBDEs), in pet dogs and cats. We also measured the residue levels of these compounds in commercially available pet foods. Chemical analyses of PCBs and OH-PCBs showed that the OH-PCB levels were 1 to 2 orders of magnitude lower in cat and dog food products than in their blood, suggesting that the origin of OH-PCBs in pet dogs and cats is PCBs ingested with their food. The major congeners of OH-/MeO-PBDEs identified in both pet food products and blood were natural products (6OH-/MeO-BDE47 and 2'OH-/MeO-BDE68) from marine organisms. In particular, higher concentrations of 6OH-BDE47 than 2'OH-BDE68 and two MeO-PBDE congeners were observed in the cat blood, although MeO-BDEs were dominant in cat foods, suggesting the efficient biotransformation of 6OH-BDE47 from 6MeO-BDE47 in cats. We performed in vitro demethylation experiments to confirm the biotransformation of MeO-PBDEs to OH-PBDEs using liver microsomes. The results showed that 6MeO-BDE47 and 2'MeO-BDE68 were demethylated to 6OH-BDE47 and 2'OH-BDE68 in both animals, whereas no hydroxylated metabolite from BDE47 was detected. The present study suggests that pet cats are exposed to MeO-PBDEs through cat food products containing fish flavors and that the OH-PBDEs in cat blood are derived from the CYP-dependent demethylation of naturally occurring MeO-PBDE congeners, not from the hydroxylation of PBDEs.

Nanotechnology for Food Packaging and Food Quality Assessment.

PubMed

Rossi, Marco; Passeri, Daniele; Sinibaldi, Alberto; Angjellari, Mariglen; Tamburri, Emanuela; Sorbo, Angela; Carata, Elisabetta; Dini, Luciana

Nanotechnology has paved the way to innovative food packaging materials and analytical methods to provide the consumers with healthier food and to reduce the ecological footprint of the whole food chain. Combining antimicrobial and antifouling properties, thermal and mechanical protection, oxygen and moisture barrier, as well as to verify the actual quality of food, e.g., sensors to detect spoilage, bacterial growth, and to monitor incorrect storage conditions, or anticounterfeiting devices in food packages may extend the products shelf life and ensure higher quality of foods. Also the ecological footprint of food chain can be reduced by developing new completely recyclable and/or biodegradable packages from natural and eco-friendly resources. The contribution of nanotechnologies to these goals is reviewed in this chapter, together with a description of portable devices ("lab-on-chip," sensors, nanobalances, etc.) which can be used to assess the quality of food and an overview of regulations in force on food contact materials. © 2017 Elsevier Inc. All rights reserved.

Fine Tuning of Antibiotic Activity by a Tailoring Hydroxylase in a Trans-AT Polyketide Synthase Pathway.

PubMed

Mohammad, Hadi H; Connolly, Jack A; Song, Zhongshu; Hothersall, Joanne; Race, Paul R; Willis, Christine L; Simpson, Thomas J; Winn, Peter J; Thomas, Christopher M

2018-04-16

The addition or removal of hydroxy groups modulates the activity of many pharmacologically active biomolecules. It can be integral to the basic biosynthetic factory or result from associated tailoring steps. For the anti-MRSA antibiotic mupirocin, removal of a C8-hydroxy group late in the biosynthetic pathway gives the active pseudomonic acid A. An extra hydroxylation, at C4, occurs in the related but more potent antibiotic thiomarinol A. We report here in vivo and in vitro studies that show that the putative non-haem-iron(II)/α-ketoglutaratedependent dioxygenase TmuB, from the thiomarinol cluster, 4-hydroxylates various pseudomonic acids whereas C8-OH, and other substituents around the tetrahydropyran ring, block enzyme action but not substrate binding. Molecular modelling suggested a basis for selectivity, but mutation studies had a limited ability to rationally modify TmuB substrate specificity. 4-Hydroxylation had opposite effects on the potency of mupirocin and thiomarinol. Thus, TmuB can be added to the toolbox of polyketide tailoring technologies for the in vivo generation of new antibiotics in the future. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Volume, nature and potential impact of advertisements on Facebook and YouTube by food brands popular in New Zealand.

PubMed

Vandevijvere, Stefanie; Aitken, Charlotte; Swinburn, Boyd

2018-04-13

To analyse extent, nature and potential impact of marketing by food and beverage brands popular in New Zealand on Facebook and YouTube. Popular food and beverage brands in New Zealand were selected from Socialbakers. Posts on Facebook pages of 45 packaged food, beverage and fast food companies over two months and YouTube channels of 15 companies over two years were analysed for nutritional quality and use of activities, promotional strategies (eg, cartoons) and premium offers (eg, competitions). The 45 brands selected made 762 Facebook posts during October-November 2016. About 28% of posts were videos and 2/3 (63%) contained at least one occasional (ie, unhealthy) food. Promotional strategies were used in 41% of posts, with a famous sportsperson/team being the most frequently used. Premium offers were used in 34% of posts, with competitions being the most frequently used. It was estimated some posts could potentially reach 10% of New Zealand adolescents. The 15 food brands selected posted about 300 videos on their YouTube channels during 2015-2016. About 84% of videos contained food marketing and 77% of products marketed were occasional. Promotional strategies and premium offers were used in 61% and 24% of videos respectively, and the most common marketing techniques were the same as on Facebook. Social media is an important medium for food marketers in New Zealand and promotional strategies and premium offers are frequently used. Methodology needs to be developed to monitor actual exposure to such advertisements.

Jagua blue derived from Genipa americana L. fruit: A natural alternative to commonly used blue food colorants?

PubMed

Brauch, J E; Zapata-Porras, S P; Buchweitz, M; Aschoff, J K; Carle, R

2016-11-01

Due to consumers' increasing health awareness, food industry aims at replacing synthetic dyes by natural counterparts. The substitution of blue synthetic dyes is particularly challenging since current natural alternatives such as phycocyanin (Spirulina) suffer from poor stability. Jagua blue (produced from Genipa americana L. fruit) might represent a potential novel blue pigment source. However, only little is known about its color properties, and application in food systems. Therefore, the blue color and the stability of Jagua blue were assessed for the first time and compared to commonly used colorants, namely, Spirulina, brilliant blue FCF (Blue no. 1), and indigo carmine (Blue no. 2). The reaction rate of Jagua blue was independent of its concentration, confirming thermal degradation to follow first-order kinetics. Between pH 3.6 and 5.0, the color hue of Jagua blue solutions was similar to that of Blue no. 2. However, Jagua blue revealed markedly higher storage stabilities (t 1/2 =86-105days) than Blue no. 2 (t 1 /2 ≤9days) and was less susceptible to acidic pH of 3.6 (t 1 /2 =86days) than Spirulina (t 1 /2 =70days). High negative b* values (blueness) of colored gelatin gels were only obtained for Jagua blue and Spirulina, and the former exhibited higher light stabilities (t 1 /2 =15days) than Spirulina gels (t 1 /2 =4days). Our findings indicate Jagua blue to be a most promising alternative to synthetic dyes, providing relevant information regarding potential food applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diversity of nonribosomal peptide synthetase and polyketide synthase gene clusters among taxonomically close Streptomyces strains.

PubMed

Komaki, Hisayuki; Sakurai, Kenta; Hosoyama, Akira; Kimura, Akane; Igarashi, Yasuhiro; Tamura, Tomohiko

2018-05-02

To identify the species of butyrolactol-producing Streptomyces strain TP-A0882, whole genome-sequencing of three type strains in a close taxonomic relationship was performed. In silico DNA-DNA hybridization using the genome sequences suggested that Streptomyces sp. TP-A0882 is classified as Streptomyces diastaticus subsp. ardesiacus. Strain TP-A0882, S. diastaticus subsp. ardesiacus NBRC 15402 T , Streptomyces coelicoflavus NBRC 15399 T , and Streptomyces rubrogriseus NBRC 15455 T harbor at least 14, 14, 10, and 12 biosynthetic gene clusters (BGCs), respectively, coding for nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs). All 14 gene clusters were shared by S. diastaticus subsp. ardesiacus strains TP-A0882 and NBRC 15402 T , while only four gene clusters were shared by the three distinct species. Although BGCs for bacteriocin, ectoine, indole, melanine, siderophores such as deferrioxamine, terpenes such as albaflavenone, hopene, carotenoid and geosmin are shared by the three species, many BGCs for secondary metabolites such as butyrolactone, lantipeptides, oligosaccharide, some terpenes are species-specific. These results indicate the possibility that strains belonging to the same species possess the same set of secondary metabolite-biosynthetic pathways, whereas strains belonging to distinct species have species-specific pathways, in addition to some common pathways, even if the strains are taxonomically close.

Food Antimicrobials Nanocarriers

PubMed Central

Blanco-Padilla, Adriana; Soto, Karen M.; Hernández Iturriaga, Montserrat

2014-01-01

Natural food antimicrobials are bioactive compounds that inhibit the growth of microorganisms involved in food spoilage or food-borne illness. However, stability issues result in degradation and loss of antimicrobial activity. Nanoencapsulation allows protection of antimicrobial food agents from unfavorable environmental conditions and incompatibilities. Encapsulation of food antimicrobials control delivery increasing the concentration of the antimicrobials in specific areas and the improvement of passive cellular absorption mechanisms resulted in higher antimicrobial activity. This paper reviews the present state of the art of the nanostructures used as food antimicrobial carriers including nanoemulsions, nanoliposomes, nanoparticles, and nanofibers. PMID:24995363

Association between traditional food consumption and motives for food choice in six European countries.

PubMed

Pieniak, Zuzanna; Verbeke, Wim; Vanhonacker, Filiep; Guerrero, Luis; Hersleth, Margrethe

2009-08-01

This study investigates the association between traditional food consumption and motives for food choice in six European countries. Cross-sectional data were collected through the TRUEFOOD pan-European consumer survey (n = 4828) with samples representative for age, gender and region in Belgium, France, Italy, Norway, Poland and Spain. Importance attached to familiarity with a product is found to be strongly and positively associated with general attitude toward traditional food as well as traditional food consumption. The importance attached to convenience was negatively related to both general attitude toward traditional food and traditional food consumption, while the importance of weight control negatively influenced the general attitude. Natural content of food was positively associated with the attitude toward traditional food and traditional food consumption. The importance of price when purchasing food failed to be significantly related with general attitude and traditional food consumption both for the pooled sample as well as within each country except in Spain. The proposed model contributes to a better understanding of factors shaping the image and influencing the consumption of traditional foods in Europe. General attitude toward traditional foods, familiarity, and importance of food naturalness emerged as drivers for traditional food consumption. Importance attached to convenience and health acted as direct barriers to traditional food consumption, whereas importance of weight control emerged as an indirect barrier through lowering general attitude toward traditional foods.

The extent and nature of food advertising to children on Spanish television in 2012 using an international food-based coding system and the UK nutrient profiling model.

PubMed

Royo-Bordonada, M Á; León-Flández, K; Damián, J; Bosqued-Estefanía, M J; Moya-Geromini, M Á; López-Jurado, L

2016-08-01

To examine the extent and nature of food television advertising directed at children in Spain using an international food-based system and the United Kingdom nutrient profile model (UKNPM). Cross-sectional study of advertisements of food and drinks shown on five television channels over 7 days in 2012 (8am-midnight). Showing time and duration of each advertisement was recorded. Advertisements were classified as core (nutrient-rich/calorie-low products), non-core, or miscellaneous based on the international system, and either healthy/less healthy, i.e., high in saturated fats, trans-fatty acids, salt, or free sugars (HFSS), according to UKNPM. The food industry accounted for 23.7% of the advertisements (4212 out of 17,722) with 7.5 advertisements per hour of broadcasting. The international food-based coding system classified 60.2% of adverts as non-core, and UKNPM classified 64.0% as HFSS. Up to 31.5% of core, 86.8% of non-core, and 8.3% of miscellaneous advertisements were for HFSS products. The percentage of advertisements for HFSS products was higher during reinforced protected viewing times (69.0%), on weekends (71.1%), on channels of particular appeal to children and teenagers (67.8%), and on broadcasts regulated by the Spanish Code of self-regulation of the advertising of food products directed at children (70.7%). Both schemes identified that a majority of foods advertised were unhealthy, although some classification differences between the two systems are important to consider. The food advertising Code is not limiting Spanish children's exposure to advertisements for HFSS products, which were more frequent on Code-regulated broadcasts and during reinforced protected viewing time. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Food Allergy

PubMed Central

Iweala, Onyinye I.; Choudhary, Shailesh K.

2018-01-01

Purpose of Review The goal of this review is to present an updated summary of the natural history of major childhood and adult food allergies and report recent advances in potential treatments for food allergy. Recent Findings The most common childhood food allergies are typically outgrown by adolescence or adulthood. However, peanut/tree nut allergies appear to more commonly persist into adulthood. Adults can develop new IgE-mediated food allergies; the most common is oral allergy syndrome. There are multiple different approaches being tried as possible treatments for food allergy. Summary The prevalence of food allergy appears to be increasing but the varied approaches to treatment are being actively pursued such that an approved modality may not be too far in the future. PMID:29623490

[Analysis of constituents of ester-type gum bases used as natural food additives].

PubMed

Tada, Atsuko; Masuda, Aino; Sugimoto, Naoki; Yamagata, Kazuo; Yamazaki, Takeshi; Tanamoto, Kenichi

2007-12-01

The differences in the constituents of ten ester-type gum bases used as natural food additives in Japan (urushi wax, carnauba wax, candelilla wax, rice bran wax, shellac wax, jojoba wax, bees wax, Japan wax, montan wax, and lanolin) were investigated. Several kinds of gum bases showed characteristic TLC patterns of lipids. In addition, compositions of fatty acid and alcohol moieties of esters in the gum bases were analyzed by GC/MS after methanolysis and hydrolysis, respectively. The results indicated that the varieties of fatty acids and alcohols and their compositions were characteristic for each gum base. These results will be useful for identification and discrimination of the ester-type gum bases.

Production of New Cladosporin Analogues by Reconstitution of the Polyketide Synthases Responsible for the Biosynthesis of this Antimalarial Agent.

PubMed

Cochrane, Rachel V K; Sanichar, Randy; Lambkin, Gareth R; Reiz, Béla; Xu, Wei; Tang, Yi; Vederas, John C

2016-01-11

The antimalarial agent cladosporin is a nanomolar inhibitor of the Plasmodium falciparum lysyl-tRNA synthetase, and exhibits activity against both blood- and liver-stage infection. Cladosporin can be isolated from the fungus Cladosporium cladosporioides, where it is biosynthesized by a highly reducing (HR) and a non-reducing (NR) iterative type I polyketide synthase (PKS) pair. Genome sequencing of the host organism and subsequent heterologous expression of these enzymes in Saccharomyces cerevisiae produced cladosporin, confirming the identity of the putative gene cluster. Incorporation of a pentaketide intermediate analogue indicated a 5+3 assembly by the HR PKS Cla2 and the NR PKS Cla3 during cladosporin biosynthesis. Advanced-intermediate analogues were synthesized and incorporated by Cla3 to furnish new cladosporin analogues. A putative lysyl-tRNA synthetase resistance gene was identified in the cladosporin gene cluster. Analysis of the active site emphasizes key structural features thought to be important in resistance to cladosporin. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Uncovering trophic positions and food resources of soil animals using bulk natural stable isotope composition.

PubMed

Potapov, Anton M; Tiunov, Alexei V; Scheu, Stefan

2018-06-19

Despite the major importance of soil biota in nutrient and energy fluxes, interactions in soil food webs are poorly understood. Here we provide an overview of recent advances in uncovering the trophic structure of soil food webs using natural variations in stable isotope ratios. We discuss approaches of application, normalization and interpretation of stable isotope ratios along with methodological pitfalls. Analysis of published data from temperate forest ecosystems is used to outline emerging concepts and perspectives in soil food web research. In contrast to aboveground and aquatic food webs, trophic fractionation at the basal level of detrital food webs is large for carbon and small for nitrogen stable isotopes. Virtually all soil animals are enriched in 13 C as compared to plant litter. This 'detrital shift' likely reflects preferential uptake of 13 C-enriched microbial biomass and underlines the importance of microorganisms, in contrast to dead plant material, as a major food resource for the soil animal community. Soil organic matter is enriched in 15 N and 13 C relative to leaf litter. Decomposers inhabiting mineral soil layers therefore might be enriched in 15 N resulting in overlap in isotope ratios between soil-dwelling detritivores and litter-dwelling predators. By contrast, 13 C content varies little between detritivores in upper litter and in mineral soil, suggesting that they rely on similar basal resources, i.e. little decomposed organic matter. Comparing vertical isotope gradients in animals and in basal resources can be a valuable tool to assess trophic interactions and dynamics of organic matter in soil. As indicated by stable isotope composition, direct feeding on living plant material as well as on mycorrhizal fungi is likely rare among soil invertebrates. Plant carbon is taken up predominantly by saprotrophic microorganisms and channelled to higher trophic levels of the soil food web. However, feeding on photoautotrophic microorganisms and non

Polyphenol-enriched berry extracts naturally modulate reactive proteins in model foods.

PubMed

Lila, Mary Ann; Schneider, Maggie; Devlin, Amy; Plundrich, Nathalie; Laster, Scott; Foegeding, E Allen

2017-12-13

Healthy foods like polyphenol-rich berries and high quality edible proteins are in demand in today's functional food marketplace, but it can be difficult to formulate convenient food products with physiologically-relevant amounts of these ingredients and still maintain product quality. In part, this is because proteins can interact with other food ingredients and precipitate destabilizing events, which can disrupt food structure and diminish shelf life. Proteins in foods can also interact with human receptors to provoke adverse consequences such as allergies. When proteins and polyphenols were pre-aggregated into stable colloidal particles prior to use as ingredients, highly palatable food formulations (with reduced astringency of polyphenols) could be prepared, and the overall structural properties of food formulations were significantly improved. All of the nutritive and phytoactive benefits of the proteins and concentrated polyphenols remained highly bioavailable, but the protein molecules in the particle matrix did not self-aggregate into networks or react with other food ingredients. Both the drainage half-life (a marker of structural stability) and the yield stress (resistance to flow) of model foams made with the protein-polyphenol particles were increased in a dose-dependent manner. Of high significance in this complexation process, the reactive allergenic epitopes of certain proteins were effectively blunted by binding with polyphenols, attenuating the allergenicity of the food proteins. Porcine macrophages produced TNF-α proinflammatory cytokine when provoked with whey protein, but, this response was blocked completely when the cells were stimulated with particles that complexed whey protein with cinnamon-derived polyphenols. Cytokine and chemokine production characteristic of allergic reactions were blocked by the polyphenols, allowing for the potential creation of hypoallergenic protein-berry polyphenol enriched foods.

Genuine and Natural: The Opinion of Teen Consumers.

PubMed

Balzan, Stefania; Fasolato, Luca; Cardazzo, Barbara; Penon, Cristiana; Novelli, Enrico

2017-01-24

Food packaging frequently reports the terms natural, 100% natural or similar. Often these indications induce consumers to purchase those products that are considered healthier and fresher. The overall goal of this study was to assess what teen consumers perceive to be genuine and natural foods. A questionnaire was distributed to the students of some high schools (lyceum, technical and professional institutes). It was completed by 349 females and 314 males, with an average age of 17.6 years. Respondents are quite interested in the information on recipes, diet, beauty and food safety; websites were important information retrieval tools. Genuine food is defined mainly as fruits and vegetables, home-made and salubrious, with less or without fat and that is good for health. Meanwhile, natural is demarcated primarily by the absence of additives and manipulation or treatments (negative impact). Also fruits and vegetables and organic production are associated to natural. The existence of a natural food preference is well described and the presence on food label may cause a wrong perception of healthfulness.

Cloning, Sequencing, and Functional Analysis of an Iterative Type I Polyketide Synthase Gene Cluster for Biosynthesis of the Antitumor Chlorinated Polyenone Neocarzilin in “Streptomyces carzinostaticus”

PubMed Central

Otsuka, Miyuki; Ichinose, Koji; Fujii, Isao; Ebizuka, Yutaka

2004-01-01

Neocarzilins (NCZs) are antitumor chlorinated polyenones produced by “Streptomyces carzinostaticus” var. F-41. The gene cluster responsible for the biosynthesis of NCZs was cloned and characterized. DNA sequence analysis of a 33-kb region revealed a cluster of 14 open reading frames (ORFs), three of which (ORF4, ORF5, and ORF6) encode type I polyketide synthase (PKS), which consists of four modules. Unusual features of the modular organization is the lack of an obvious acyltransferase domain on modules 2 and 4 and the presence of longer interdomain regions more than 200 amino acids in length on each module. Involvement of the PKS genes in NCZ biosynthesis was demonstrated by heterologous expression of the cluster in Streptomyces coelicolor CH999, which produced the apparent NCZ biosynthetic intermediates dechloroneocarzillin A and dechloroneocarzilin B. Disruption of ORF5 resulted in a failure of NCZ production, providing further evidence that the cluster is essential for NCZ biosynthesis. Mechanistic consideration of NCZ formation indicates the iterative use of at least one module of the PKS, which subsequently releases its product by decarboxylation to generate an NCZ skeleton, possibly catalyzed by a type II thioesterase encoded by ORF7. This is a novel type I PKS system of bacterial origin for the biosynthesis of a reduced polyketide chain. Additionally, the protein encoded by ORF3, located upstream of the PKS genes, closely resembles the FADH2-dependent halogenases involved in the formation of halometabolites. The ORF3 protein could be responsible for the halogenation of NCZs, presenting a unique example of a halogenase involved in the biosynthesis of an aliphatic halometabolite. PMID:15328113

Natural life styles library: energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1974-01-01

Three new sections appear in this issue. Information from the readers on good products, books, catalogues, places to eat and sleep, good doctors, foods, farms, natural cosmetics, or nutritionists is provided. Another section is devoted to housing to serve as an information exchange. This section is open to comments from readers on house construction, about materials, or alternate energy sources. The third new section deals with wild food and natural food recipes. Articles in this issue deal with wood stoves; solar energy in use; wood dome planner for NLS or communal living; farming information; the thriftchanger, a device for heatingmore » and cooling; maintaining the old truck; and how to build a hotbed for all seasons. Information on Jerusalem artichokes, pond lilies, pumpkin pies, persimmons, rose hips, sunflowers, and seed gathering is included in the food section. Information on Alternate Energy Access and Consumers in a Food Economy are two additional articles. Two nature poems are included. Reviews on an organic primer, shelter and survival data, the mountain people, an herbal guide, super beauty and natural cosmetics, a review of six cookbooks, and a healthy family cookbook are presented. (MCW)« less

Marine actinobacteria associated with marine organisms and their potentials in producing pharmaceutical natural products.

PubMed

Valliappan, Karuppiah; Sun, Wei; Li, Zhiyong

2014-09-01

Actinobacteria are ubiquitous in the marine environment, playing an important ecological role in the recycling of refractory biomaterials and producing novel natural products with pharmic applications. Actinobacteria have been detected or isolated from the marine creatures such as sponges, corals, mollusks, ascidians, seaweeds, and seagrass. Marine organism-associated actinobacterial 16S rRNA gene sequences, i.e., 3,003 sequences, deposited in the NCBI database clearly revealed enormous numbers of actinobacteria associated with marine organisms. For example, RDP classification of these sequences showed that 112 and 62 actinobacterial genera were associated with the sponges and corals, respectively. In most cases, it is expected that these actinobacteria protect the host against pathogens by producing bioactive compounds. Natural products investigation and functional gene screening of the actinobacteria associated with the marine organisms revealed that they can synthesize numerous natural products including polyketides, isoprenoids, phenazines, peptides, indolocarbazoles, sterols, and others. These compounds showed anticancer, antimicrobial, antiparasitic, neurological, antioxidant, and anti-HIV activities. Therefore, marine organism-associated actinobacteria represent an important resource for marine drugs. It is an upcoming field of research to search for novel actinobacteria and pharmaceutical natural products from actinobacteria associated with the marine organisms. In this review, we attempt to summarize the present knowledge on the diversity and natural products production of actinobacteria associated with the marine organisms, based on the publications from 1991 to 2013.

Pectin in foods

USDA-ARS?s Scientific Manuscript database

Pectin, a complex polysaccharide, is a major component of non-lignified cell walls of dicotyledonous and some monocotyledonous plants. Its food-related technological functions are numerous and mirror many of its biological functions. As a naturally occurring component of raw or processed foods and a...

Naturally Occurring Tolerance Acquisition to Foods in Previously Allergic Children is Characterized by Antigen Specificity and Associated with Increased Subsets of Regulatory T cells

PubMed Central

Qamar, Nashmia; Fishbein, Anna B.; Erickson, Kristin A.; Cai, Miao; Szychlinski, Christine; Bryce, Paul J.; Schleimer, Robert P.; Fuleihan, Ramsay L.; Singh, Anne Marie

2015-01-01

Background Food allergy affects approximately 6–8% of children, and increasing in prevalence. Some children naturally outgrow their food allergy without intervention but the mechanisms by which this occurs remain poorly understood. We sought to investigate the role of regulatory T cells in the development of naturally acquired tolerance. Methods Fifty-eight children (1 to 18 years) with either egg or peanut allergy, recent acquisition of natural tolerance to egg or peanut, or no food allergy were studied. Peripheral blood mononuclear cells (PBMC) from these groups were stimulated with relevant antigen for 48 hours and flow cytometry performed to characterize both surface (CD3, CD4, CD25, CD14, CD19, CD127) and intracellular markers (IL-10, Foxp3, and IL-5). Results Resting PBMC from naturally tolerant patients had significantly increased CD3+CD4+CD25+CD127loFoxp3+ cells, when compared to allergic or control patients [mean 6.36 vs 2.37 vs 2.62%, respectively, p<0.05]. Upon stimulation with relevant antigen, naturally tolerant patients also had increased IL-10-expressing CD25+CD127lo cells [6.33 vs 1.65 vs 0.7, p<0.01], Foxp3+ cells [mean 12.6 vs 5.42 vs 3%, p<0.01] and CD4+ cells [mean 4.48 vs 1.59 vs 0.87%, p<0.01]; the increase was not observed in PBMCs from allergic or control patients. Additionally, this upregulation was only seen with relevant antigen stimulation and not upon stimulation with unrelated antigen. Conclusion The increased CD3+CD4+CD25+CD127lo cells at baseline and upon stimulation and increased induction of IL-10-producing cells of several types, including Tr1 cells, from naturally tolerant patients suggests an important role for regulatory T cell subsets in the acquisition of natural tolerance. PMID:25989379

The natural food colorant Peonidin from cranberries as a potential radical scavenger - A DFT based mechanistic analysis.

PubMed

Rajan, Vijisha K; Hasna, C K; Muraleedharan, K

2018-10-01

A theoretical evaluation of the antioxidant property of a natural food colorant Peonidin has been performed. The most suitable mechanism for explaining the radical scavenging capacity of Peonidin is the Hydrogen Atom Transfer and the most active site for radical formation is position 3 and is confirmed through Mulliken charge analysis, pKa value evaluation, Bond Dissociation Energy values, and Natural Bond Orbital analysis. Position 3 and 5 in Peonidin exists in blood as deprotonated as their pKa values are lower than the pH of blood. Peonidin is highly reactive than Quercetin and less stable than flavan-3-ols due to the small band gap. Global descriptor analysis shows that PN prefers to accept electrons than to donate. The effect of number of OH groups and the nature of substituents are well explained through this work. Copyright © 2018 Elsevier Ltd. All rights reserved.

Production of the natural iron chelator deferriferrichrysin from Aspergillus oryzae and evaluation as a novel food-grade antioxidant.

PubMed

Todokoro, Takehiko; Fukuda, Katsuharu; Matsumura, Kengo; Irie, Motoko; Hata, Yoji

2016-07-01

Deferriferrichrysin (Dfcy) is a siderophore found in foods fermented by Aspergillus oryzae and is a promising candidate for an antioxidant food additive because of its high binding constant toward iron. However, the Dfcy concentration is typically low in foods and cultures. We optimised culture conditions to improve Dfcy production to 2800 mg L(-1) from 22.5 mg L(-1) under typical conditions. Then, we evaluated the potential of Dfcy as a food additive by measuring its safety, stability, and antioxidant activity. Dfcy was sufficiently stable that over 90% remained after pasteurisation at 63 °C for 30 min at pH 3-11, or after sterilisation at 120 °C for 4 min at pH 4-6. Dfcy showed high antioxidant activity in an oil-in-water model, where inhibition of lipid oxidation was measured by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) assays. Dfcy decreased PV and TBARS by 83% and 75%, respectively. Antioxidant activity of Dfcy was equal to or higher than that of the synthetic chelator EDTA. Our study provides the first practical method for production of Dfcy. Dfcy can be a novel food-grade antioxidant and the first natural alternative to the synthesised iron chelator EDTA. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

The perceived healthiness of functional foods. A conjoint study of Danish, Finnish and American consumers' perception of functional foods.

PubMed

Bech-Larsen, Tino; Grunert, Klaus G

2003-02-01

Functional foods presumably enable the consumer to lead a healthier life without changing eating habits. Whether consumers accept this proposition or not is potentially influenced by their perceptions of the healthiness of the processing methods, enrichment components, food-types, and health claims used in the production and marketing of functional foods. Because consumers may perceive functional enrichment as interfering with nature, cultural values pertaining to man's manipulation of nature may also influence consumer acceptance of functional foods. The purpose of the study described here is to clarify to which extent Danish, Finnish and American consumers' perceptions of the healthiness of functional foods are explained by the factors mentioned above. The general results indicate that values pertaining to man's manipulation of nature is only modestly related to the acceptance of functional foods, whereas the use of different health claims, processing methods, enrichments, product types, and especially the interactions between the two latter, are important determinants of consumers' perceptions of the healthiness of functional foods.

Trade-offs for food production, nature conservation and climate limit the terrestrial carbon dioxide removal potential.

PubMed

Boysen, Lena R; Lucht, Wolfgang; Gerten, Dieter

2017-10-01

Large-scale biomass plantations (BPs) are a common factor in climate mitigation scenarios as they promise double benefits: extracting carbon from the atmosphere and providing a renewable energy source. However, their terrestrial carbon dioxide removal (tCDR) potentials depend on important factors such as land availability, efficiency of capturing biomass-derived carbon and the timing of operation. Land availability is restricted by the demands of future food production depending on yield increases and population growth, by requirements for nature conservation and, with respect to climate mitigation, avoiding unfavourable albedo changes. We integrate these factors in one spatially explicit biogeochemical simulation framework to explore the tCDR opportunity space on land available after these constraints are taken into account, starting either in 2020 or 2050, and lasting until 2100. We find that assumed future needs for nature protection and food production strongly limit tCDR potentials. BPs on abandoned crop and pasture areas (~1,300 Mha in scenarios of either 8.0 billion people and yield gap reductions of 25% until 2020 or 9.5 billion people and yield gap reductions of 50% until 2050) could, theoretically, sequester ~100 GtC in land carbon stocks and biomass harvest by 2100. However, this potential would be ~80% lower if only cropland was available or ~50% lower if albedo decreases were considered as a factor restricting land availability. Converting instead natural forest, shrubland or grassland into BPs could result in much larger tCDR potentials ̶ but at high environmental costs (e.g. biodiversity loss). The most promising avenue for effective tCDR seems to be improvement of efficient carbon utilization pathways, changes in dietary trends or the restoration of marginal lands for the implementation of tCDR. © 2017 John Wiley & Sons Ltd.

Bacteriophage Applications for Food Production and Processing

PubMed Central

Moye, Zachary D.; Woolston, Joelle; Sulakvelidze, Alexander

2018-01-01

Foodborne illnesses remain a major cause of hospitalization and death worldwide despite many advances in food sanitation techniques and pathogen surveillance. Traditional antimicrobial methods, such as pasteurization, high pressure processing, irradiation, and chemical disinfectants are capable of reducing microbial populations in foods to varying degrees, but they also have considerable drawbacks, such as a large initial investment, potential damage to processing equipment due to their corrosive nature, and a deleterious impact on organoleptic qualities (and possibly the nutritional value) of foods. Perhaps most importantly, these decontamination strategies kill indiscriminately, including many—often beneficial—bacteria that are naturally present in foods. One promising technique that addresses several of these shortcomings is bacteriophage biocontrol, a green and natural method that uses lytic bacteriophages isolated from the environment to specifically target pathogenic bacteria and eliminate them from (or significantly reduce their levels in) foods. Since the initial conception of using bacteriophages on foods, a substantial number of research reports have described the use of bacteriophage biocontrol to target a variety of bacterial pathogens in various foods, ranging from ready-to-eat deli meats to fresh fruits and vegetables, and the number of commercially available products containing bacteriophages approved for use in food safety applications has also been steadily increasing. Though some challenges remain, bacteriophage biocontrol is increasingly recognized as an attractive modality in our arsenal of tools for safely and naturally eliminating pathogenic bacteria from foods. PMID:29671810

Food, home and health: the meanings of food amongst Bengali Women in London

PubMed Central

2014-01-01

Background This paper explores the nature of food and plants and their meanings in a British Bengali urban context. It focuses on the nature of plants and food in terms of their role in home making, transnational connections, generational change and concepts of health. Methods An ethnographic approach to the research was taken, specific methods included participant observation, focus group discussions and semi-structured interviews. Thirty women of Bengali origin were mostly composed of “mother” and “daughter” pairs. The mothers were over 45 years old and had migrated from Bangladesh as adults and their grown-up daughters grew up in the UK. Results Food and plants play an important role in the construction of home “here” (London) while continuing to connect people to home “there” (Sylhet). This role, however, changes and is re-defined across generations. Looking at perceptions of “healthy” and “unhealthy” food, particularly in the context of Bengali food, multiple views of what constitutes “healthy” food exist. However, there appeared to be little two-way dialogue about this concept between the research participants and health professionals. This seems to be based on “cultural” and power differences that need to be addressed for a meaningful dialogue to occur. Conclusion In summary, this paper argues that while food is critical to the familial spaces of home (both locally and globally), it is defined by a complex interplay of actors and wider meanings as illustrated by concepts of health and what constitutes Bengali food. Therefore, we call for greater dialogue between health professionals and those they interact with, to allow for an enhanced appreciation of the dynamic nature of food and plants and the diverse perceptions of the role that they play in promoting health. PMID:24886061

StandFood: Standardization of Foods Using a Semi-Automatic System for Classifying and Describing Foods According to FoodEx2

PubMed Central

Eftimov, Tome; Korošec, Peter; Koroušić Seljak, Barbara

2017-01-01

The European Food Safety Authority has developed a standardized food classification and description system called FoodEx2. It uses facets to describe food properties and aspects from various perspectives, making it easier to compare food consumption data from different sources and perform more detailed data analyses. However, both food composition data and food consumption data, which need to be linked, are lacking in FoodEx2 because the process of classification and description has to be manually performed—a process that is laborious and requires good knowledge of the system and also good knowledge of food (composition, processing, marketing, etc.). In this paper, we introduce a semi-automatic system for classifying and describing foods according to FoodEx2, which consists of three parts. The first involves a machine learning approach and classifies foods into four FoodEx2 categories, with two for single foods: raw (r) and derivatives (d), and two for composite foods: simple (s) and aggregated (c). The second uses a natural language processing approach and probability theory to describe foods. The third combines the result from the first and the second part by defining post-processing rules in order to improve the result for the classification part. We tested the system using a set of food items (from Slovenia) manually-coded according to FoodEx2. The new semi-automatic system obtained an accuracy of 89% for the classification part and 79% for the description part, or an overall result of 79% for the whole system. PMID:28587103

StandFood: Standardization of Foods Using a Semi-Automatic System for Classifying and Describing Foods According to FoodEx2.

PubMed

Eftimov, Tome; Korošec, Peter; Koroušić Seljak, Barbara

2017-05-26

The European Food Safety Authority has developed a standardized food classification and description system called FoodEx2. It uses facets to describe food properties and aspects from various perspectives, making it easier to compare food consumption data from different sources and perform more detailed data analyses. However, both food composition data and food consumption data, which need to be linked, are lacking in FoodEx2 because the process of classification and description has to be manually performed-a process that is laborious and requires good knowledge of the system and also good knowledge of food (composition, processing, marketing, etc.). In this paper, we introduce a semi-automatic system for classifying and describing foods according to FoodEx2, which consists of three parts. The first involves a machine learning approach and classifies foods into four FoodEx2 categories, with two for single foods: raw (r) and derivatives (d), and two for composite foods: simple (s) and aggregated (c). The second uses a natural language processing approach and probability theory to describe foods. The third combines the result from the first and the second part by defining post-processing rules in order to improve the result for the classification part. We tested the system using a set of food items (from Slovenia) manually-coded according to FoodEx2. The new semi-automatic system obtained an accuracy of 89% for the classification part and 79% for the description part, or an overall result of 79% for the whole system.

LAE1 regulates expression of multiple secondary metabolite gene clusters in Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

The filamentous fungus Fusarium verticillioides can cause disease of maize and is capable of producing the polyketide derived mycotoxins called fumonisins. Fumonisin contamination of maize kernels is a food safety concern. Fumonisins have been implicated in human esophageal cancer as well as in cau...

Construction of ivermectin producer by domain swaps of avermectin polyketide synthase in Streptomyces avermitilis.

PubMed

Zhang, Xiaolin; Chen, Zhi; Li, Meng; Wen, Ying; Song, Yuan; Li, Jilun

2006-10-01

Ivermectin, 22, 23-dihydroavermectin B1, is commercially important in human, veterinary medicine, and pesticides. It is currently synthesized by chemical reduction of the double bond between C22 and C23 of avermectins B1, which are a mixture of B1a (>80%) and B1b (<20%) produced by fermentation of Streptomyces avermitilis. The cost of ivermectin is much higher than that of avermectins B1 owing to the necessity of region-specific hydrogenation at C22-C23 of avermectins B1 with rhodium chloride as the catalyst for producing ivermectin. Here we report that ivermectin can be produced directly by fermentation of recombinant strains constructed through targeted genetic engineering of the avermectin polyketide synthase (PKS) in S. avermitilis Olm73-12, which produces only avermectins B and not avermectins A and oligomycin. The DNA region encoding the dehydratase (DH) and ketoreductase (KR) domains of module 2 from the avermectin PKS in S. avermitilis Olm73-12 was replaced by the DNA fragment encoding the DH, enoylreductase, and KR domains from module 4 of the pikromycin PKS of Streptomyces venezuelae ATCC 15439 using a gene replacement vector pXL211. Twenty-seven of mutants were found to produce a small amount of 22, 23-dihydroavermectin B1a and avermectin B1a and B2a by high performance liquid chromatography and liquid chromatography mass spectrometry analysis. This study might provide a route to the low-cost production of ivermectin by fermentation.

Alternatives to those artificial FD&C food colorants.

PubMed

Wrolstad, Ronald E; Culver, Catherine A

2012-01-01

Replacement of artificial food dyes with natural colorants is a current marketing trend, notwithstanding the fact that neither the United States nor the European Union (EU) has defined natural with respect to food colors. Consumer groups have concerns over the safety of synthetic colorants, and in addition, many of the naturally derived colorants provide health benefits. Food scientists frequently have the assignment of replacing artificial colorants with natural alternatives. This can be challenging, as naturally derived colorants are usually less stable, and all desired hues might, in fact, not be obtainable. In this review, the chemical and physical properties, limitations, and more suitable applications for those colorants that are legally available as substitutes for the synthetic colorants are summarized. Issues and challenges for certain foods are discussed, and in addition, colorants that may be available in the future are briefly described.

Parents' food choice motives and their associations with children's food preferences.

PubMed

Russell, Catherine G; Worsley, Anthony; Liem, Djin G

2015-04-01

The objective was to investigate parents' motives for selecting foods for their children and the associations between these motives and children's food preferences. Cross-sectional survey. A modified version of the Food Choice Questionnaire was used to assess parents' food choice motives. Parents also reported children's liking/disliking of 176 food and beverage items on 5-point Likert scales. Patterns of food choice motives were examined with exploratory principal component analysis. Associations between motives and children's food preferences were assessed with linear regression while one-way and two-way ANOVA were used to test for sociodemographic differences. Two Australian cities. Parents (n 371) of 2-5-year-old children. Health, nutrition and taste were key motivators for parents, whereas price, political concerns and advertising were among the motives considered least important. The more parents' food choice for their children was driven by what their children wanted, the less children liked vegetables (β =-0·27, P<0·01), fruit (β=-0·19, P<0·01) and cereals (β=-0·28, P<0·01) and the higher the number of untried foods (r=0·17, P<0·01). The reverse was found for parents' focus on natural/ethical motives (vegetables β=0·17, P<0·01; fruit β=0·17, P<0·01; cereals β=0·14, P=0·01). Health and nutrition motives bordered on statistical significance as predictors of children's fruit and vegetable preferences. Although parents appear well intentioned in their motives for selecting children's foods, there are gaps to be addressed in the nature of such motives (e.g. selecting foods in line with the child's desires) or the translation of health motives into healthy food choices.

Ultrasound assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review.

PubMed

Chemat, Farid; Rombaut, Natacha; Sicaire, Anne-Gaëlle; Meullemiestre, Alice; Fabiano-Tixier, Anne-Sylvie; Abert-Vian, Maryline

2017-01-01

This review presents a complete picture of current knowledge on ultrasound-assisted extraction (UAE) in food ingredients and products, nutraceutics, cosmetic, pharmaceutical and bioenergy applications. It provides the necessary theoretical background and some details about extraction by ultrasound, the techniques and their combinations, the mechanisms (fragmentation, erosion, capillarity, detexturation, and sonoporation), applications from laboratory to industry, security, and environmental impacts. In addition, the ultrasound extraction procedures and the important parameters influencing its performance are also included, together with the advantages and the drawbacks of each UAE techniques. Ultrasound-assisted extraction is a research topic, which affects several fields of modern plant-based chemistry. All the reported applications have shown that ultrasound-assisted extraction is a green and economically viable alternative to conventional techniques for food and natural products. The main benefits are decrease of extraction and processing time, the amount of energy and solvents used, unit operations, and CO 2 emissions. Copyright © 2016 Elsevier B.V. All rights reserved.