Arachidonic Acid : Dietary Sources and General Functions [1 ed.] 9781622575152, 9781622574810

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Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved. Arachidonic Acid : Dietary Sources and General Functions, Nova Science Publishers, Incorporated, 2012. ProQuest Ebook Central,

Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved. Arachidonic Acid : Dietary Sources and General Functions, Nova Science Publishers, Incorporated, 2012. ProQuest Ebook Central,

BIOCHEMISTRY RESEARCH TRENDS

ARACHIDONIC ACID

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DIETARY SOURCES AND GENERAL FUNCTIONS

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BIOCHEMISTRY RESEARCH TRENDS

ARACHIDONIC ACID DIETARY SOURCES AND GENERAL FUNCTIONS

Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

GERARD G. DUMANCAS BEFRIKA S. MURDIANTI AND EDRALIN A. LUCAS

EDITORS

New York

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All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic, tape, mechanical photocopying, recording or otherwise without the written permission of the Publisher. For permission to use material from this book please contact us: Telephone 631-231-7269; Fax 631-231-8175 Web Site: http://www.novapublishers.com NOTICE TO THE READER The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers’ use of, or reliance upon, this material. Any parts of this book based on government reports are so indicated and copyright is claimed for those parts to the extent applicable to compilations of such works.

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Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. Additional color graphics may be available in the e-book version of this book. Library of Congress Cataloging-in-Publication Data

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Arachidonic Acid : Dietary Sources and General Functions, Nova Science Publishers, Incorporated, 2012. ProQuest Ebook Central,

Contents Preface

vii

Part I: Dietary Sources Chapter 1

Chapter 2

Accumulation of Arachidonic Acid in a Green Microalga, Myrmecia Incisa H4301, Enhanced by Nitrogen Starvation and its Molecular Regulation Mechanisms L. L. Ouyang, H. Li, F. Liu, M. Tong, S. Y. Yu and Z.-G. Zhou Arachidonic Acid Food Sources and Recommendation for the Vegetarian Randall D. Maples

1

21

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Part 2: General Functions Chapter 3

Chapter 4

Chapter 5

Effects of Dietary Arachidonic Acid on Cardiovascular Disease Dipti Mangal, Cornelius E. Uboh and Lawrence R. Soma Influence of Arachidonic Acid on the Endocrine Response to Stress Amy Tse, Andy K. Lee and Frederick W. Tse Control of Arachidonic Acid Levels by Ceramide 1-Phosphate and Its Impact in Cell Biology Antonio Gómez-Muñoz , Miguel Trueba, Patricia Gangoiti, Lide Arana, Io-Guané Rivera, Marta Ordoñez and Alberto Ouro

33

51

63

Chapter 6

Arachidonic Acid, Oxidative Stress and Cancer Mohammed El Hafidi, Vianey Nava Agilar and Angélica Ruiz Ramírez.

75

Chapter 7

Arachidonic Acid and Coronary Artery Disease Masayuki Ueeda and Shozo Kusachi

91

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vi Chapter 8

Chapter 9

Chapter 10

Chapter 11

Chapter 12

Contents Arachidonic Acid, Metabolic Syndrome and Alternative Therapeutic Agents Guadalupe Baños, Roxana Carbó and Israel Pérez-Torres

115

Participation of Arachidonic Acid and Its Metabolites in Insulin Resistance Israel Pérez-Torres and Guadalupe Baños

133

Long-Term Supplemental Arachidonic Acid Preserves Hippocampal Cognitive Function Manabu Sakakibara

161

Arachidonic Acid and Brain Development: Implications in the Offspring of Diabetic Pregnant Women Jinping Zhao and Hope A. Weiler

189

Arachidonic Acid and Renal Function Gerard G. Dumancas, Befrika Murdianti and Edralin A. Lucas

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Index

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237

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Preface The first isolation of arachidonic acid (AA) can be traced back in 1907 from liver lipids. However, its functions and importance are not often discussed in the area of lipidomics. With the many scientific results regarding AA and its metabolism, it is often times hard to find a good resource of AA in its entirety because most discussions will cover the entire ω-6 or both ω-6 and ω-3 fats. This book covers an interesting discussion of the sources and general functions of AA. It is divided into two parts. The first three chapters discuss the sources while chapters four to twelve discuss the general functions of AA. It is interesting to note that in part two of the book, the association of AA to endocrine response to stress, oxidative stress and cancer, coronary artery disease, metabolic syndrome, insulin resistance, brain development, and renal function are discussed. The association of AA to the mentioned disease states and functions will provide more detailed information for readers interested in understanding AA. While this book is in its first edition, it is the hope of the editors that the succeeding editions will give more insights about AA in its entirety. It is also the hope of the editors that this book will provide a useful guide for readers wanting to learn more about AA, its dietary sources and general functions. The editors would like to thank the authors coming from various parts of the world for their tremendous amount of time and effort in making this book possible. Surely, their knowledge and expertise are essential for the development of this book. The restless dedication of the editors is also acknowledged. Lastly, we also thank Nova Science Publishers for the invitation and making this book possible for publication.

Arachidonic Acid : Dietary Sources and General Functions, Nova Science Publishers, Incorporated, 2012. ProQuest Ebook Central,

Gerard G. Dumancas Befrika Murdianti Edralin A. Lucas

Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved. Arachidonic Acid : Dietary Sources and General Functions, Nova Science Publishers, Incorporated, 2012. ProQuest Ebook Central,

Copyright © 2012. Nova Science Publishers, Incorporated. All rights reserved.

Part I: Dietary Sources

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In: Arachidonic Acid: Dietary Sources and General Functions ISBN: 978-1-62257-481-0 Editors: G.G. Dumancas, B.S. Murdianti, E.A. Lucas © 2013 Nova Science Publishers, Inc.

Chapter 1

Accumulation of Arachidonic Acid in a Green Microalga, Myrmecia Incisa H4301, Enhanced by Nitrogen Starvation and its Molecular Regulation Mechanisms L. L. Ouyang, H. Li, F. Liu, M. Tong, S. Y. Yu and Z.-G. Zhou*

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Key Laboratory of Genetic Resources and Applications in Aquaculture, the Ministry of Agriculture, and Aquaculture E-Institute of Shanghai Municipal Education Commission, Shanghai Ocean University, Shanghai, China

Abstract Myrmecia incisa H4301 is a coccoid freshwater green microalga. Both the phylogeny inferred from 18S rRNA and rbcS sequences, and the ultrastructure observation suggest

that this microalga should keep the name Myrmecia incisa as described by Reisigl, rather than the genus Parietochloris as proposed by Watanabe et al. This microalga is characterized as an oleaginous species with cellular arachidonic acid (20:4 -6, AA) accounting for 7% of its dry weight biomass. Seventy-six percent of this AA was found to be stored in the form of neutral lipids after being cultivated under a nitrogen starvation stress for 27 days. The main pathway of AA biosynthesis in M. incisa H4301 suggested that the linoleic acid (18:2 -6, LA) was first desaturated to γ-linolenic acid (18:3 -6, GLA) and then elongated to di-homo-γ-linolenic acid (20:3 -6, DGLA) and subsequently desaturated to AA, in which 12, 6, and 5 fatty acid desaturases and 6 elongase (designated as MiΔ12FAD, MiΔ6FAD, MiΔ5FAD and MiΔ6FAE, respectively) play important roles. In addition, a partial LA could take part in -linolenic acid (20:3 3, ALA) biosynthesis by 3 desaturase (designated as Mi 3FAD) catalysis. All these enzymes were encoded by the genes designated as MiΔ12FAD, MiΔ6FAD, MiΔ5FAD, Mi 3FAD and MiΔ6FAE, respectively. These genes were cloned and characterized, and *

E-mail address: [email protected].

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L.L. Ouyang, H. Li, F. Liu et al. were separated by several introns. A neighbor-jointing phylogenetic tree, inferred from the deduced amino acids of the mentioned four fatty acid desaturases (FADs), indicated that MiΔ5FAD was clustered with MiΔ6FAD, whereas Mi 3FAD was homologous to and might evolve from MiΔ12FAD. As estimated by a series of quantitative real-time Polymerase Chain Reaction (q-rt-PCR), transcription of MiΔ12FAD, MiΔ6FAD, MiΔ5FAD and MiΔ6FAE in this microalga increased during the course of nitrogen starvation. The percentage of GLA, DGLA and AA, which were catalyzed by Mi 6FAD, MiΔ6FAE and Mi 5FAD, respectively, increased with the transcription of their corresponding genes. In contrast, the transcription of Mi 3FAD and percentage of ALA, which were catalyzed by its encoded enzyme, significantly declined under the nitrogen starvation stress. These results demonstrate that the expression of these genes coordinated for AA biosynthesis in M. incisa H4301 to adapt to the nitrogen starvation stress.

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Introduction Arachidonic acid (20:4 -6, AA) is an -6 polyunsaturated fatty acid (PUFA). It is one of the major components of the brain membrane’s phospholipids and is of great nutritional importance, similar to that of docosahexaenoic acid (22:6 -3, DHA). The two fatty acids (FAs) make up approximately 20% of the total FAs in the mammallian brain [1]. AA is necessary for the repair and growth of skeletal muscle tissues [2] and is a precursor of numerous eicosanoids, such as the prostaglandins (hormone-like chemical messengers) and thromboxanes involved in platelet aggregation and blood clotting [3]. Thus, it plays important roles in cell regulation. AA present in human milk, along with DHA [4, 5], is considered an essential nutrient during the early development of infants and is suggested to be added into the baby’s milk formula [6]. In organisms, AA can be synthesized from LA by desaturation and elongation processes (Figure 1). However, like humans, other mammals also cannot synthesize LA due to the lack of ability to insert double bonds between the 9th and 10th carbon (from the carboxyl end) based on the 18-C backbone (Figure 1). This FA is, thus, provided for humans by plants, microbial and fish sources, and is capable of being subsequently converted to AA [7]. The main oil sources that are relatively rich in C18 PUFAs are the seeds of some plants and molds [8], but very long chain PUFAs consisting of more than C18 structures can seldom be synthesized by higher plants in any significant amounts owing to the lack of requisite enzymes (such as fatty acid elongase (FAE) [9]). On the other hand, fish oil, certain fungi, marine bacteria, algae and mosses are rich in C20 or higher PUFAs, such as AA and DHA [10-15]. It was not until the late 1990s did the porcine liver become the main commercial source of AA. However, the low content of AA made porcine livers an inappropriate source [15]. Micro-organisms have been found to intracellularly accumulate AA in a significant amount [16-18], and commercial attention has been paid to oleaginous filamentous fungi. At present, Mortierella, which can be found on almost any substrate and commonly in soil, is studied as a practical source of AA [11, 15, 19-23]. In particular, M. alpina 1S-4 has been regarded as a unique industrial strain and as a model for lipogenesis studies [24]. The advantages of using this oleaginous filamentous fungus to produce AA include its relatively clear genetic background of AA biosynthesis [22, 25-32], and its ability to incorporate and convert exogenous FAs (such as ALA) [33-36]. Despite these advantages, the major obstacle

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Accumulation of Arachidonic Acid in a Green Microalga …

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in the way of regarding it as a commercial source is the high cost of large-scale fermentation. In contrast, autotrophic oleaginous single cells like microalgae, for instance, have the capacity to use and convert simple minerals and enormous amounts of CO2 into biomass, and several species are able to accumulate AA simultaneously as well. Therefore, they might be one of the ideal and potential commercial sources for AA.

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Figure 1. Two possible biosynthesis pathway of AA from LA. The chemical structures of LA, GLA, DGLA, AA and eicosadienoic acid (20:2 -6, EDA) are also presented.

In 1962, Haines et al. [37] found that AA not only existed in animal lipids, but also in a phytoflagellate, Ochromonas danica, and the content of AA in its cells accounted for 11% of the total FAs. Subsequently, AA was confirmed to be present in Euglena gracilis and in a red microalga, Porphyridium cruentum [38]. In general, the nutritional components of a medium (i.e., nitrogen and phosphate source [39]), light intensity [40, 41], temperature [42, 43], salinity [44], pH [45, 46] are the impact factors for the FA composition in algae, among which nitrogen starvation most significantly affects lipid biosynthesis and accumulation [47]. The high AA content (2.9% of dry weight) of P. cruentum was obtained in the stationary phase or under nitrogen starvation [48]. In Phaeodactylum tricornutum [49], Stephanodiscus minutulus [50], Parietochloris incisa [51], Isochrysis aff. galbana [52], nitrogen starvation can stimulate the increase of cell lipids, especially of triacylglycerol (TAG), a neutral lipid that is convenient for extraction and biodiesel production. A coccoid freshwater green microalga from the Culture Collection of Algae of Charles University of Prague (CAUP), M. incisa H4301 (Figure 2), has been found to be an AA-rich producer [39, 53, 54], especially when grown under nitrogen starvation (7% of dry weight); Seventy-six percent of AA accumulated in the form of TAG (see next sections). The algal cells usually aggregate together (Figure 2) so that it is easy to settle down to markedly reduce the harvesting cost. This chapter will discuss: molecular and ultrastructural evidence for taxonomy, the effects of nitrogen starvation on the growth and accumulation of FAs, and the characteristics of related genes and their coordinated transcription for AA biosynthesis under nitrogen starvation.

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L.L. Ouyang, H. Li, F. Liu et al.

Figure 2. Light micrograph of M. incisa H4301. The chloroplasts are green and incised. The bright spots in the cells represent oil bodies.

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Molecular and Ultrastructural Evidence for Taxonomy of M. incisa H4301 Myrmecia incisa H4301, an AA-rich producer [39, 53, 54], was first classified by Reisigl [55]. It belongs to Trebouxiophyceae, Chlorophyta, but its taxonomic position is still in debate. In CAUP, a strain, H4301, is named Myrmecia incisa Reisigl. In Romania, it is named Lobococcus incisus (Reisigl) Reisigl [56]. In 1996, Watanabe et al. [57] proposed that an isolated strain of M. incisa from the soil of Mt. Tateyama in Japan should be reclassified into a different genus, Parietochloris incisa (Reisigl) Watanabe comb. nov., due to the observation of pyrenoid and the zoospores with a counterclockwise basal body orientation. Subsequently, Karsten et al. [58] suggested that this species be designated as Lobosphaera incisa (Reigisl) U. Karsten on the basis of the rRNA sequence’s phylogeny and the presence of an ultravioletabsorbing mycosporine-like amino acid. Based on a cDNA library from mixture cells of complete medium cultures and nitrogenstarvation cultures from M. incisa H4301, 18S rRNA and ribulose 1, 5-bisphosphate carboxylase/oxygenase, small subunit (rbcS) genes were screened [59]. Thereafter, two independent phylogenic trees were constructed with neighbor-joining (NJ) and maximum parsimony (MP) methods (Figure 3) in the Molecular Evolutionary Genetics Analysis (MEGA) software version 4.0 [60]. Seven species in the genus Myrmecia, which include M. globosa Printz., M. incisa Reisigl., M. macronucleata (Deason) V. andr. comb. nov., M. biatorellae (Tschermak-Woess et Plessl) Boye-Peterson, M. bisecta Reisigl., M. astigmatica Vinatzer., and M. reticulata Tschermak-Woess, were described and reviewed by Andreyeva [61]. They all belong to the class, Trebouxiophyceae, as indicated by Friedl [62] by their use of a small subunit of ribosomal RNA genes. In addition, the phylogenic tree (Figure 3A) inferred from rbcS amino acid sequences provided another molecular evidence that M. incisa H4301 is one species of this class. Therefore, it is certain that Myrmecia is in the Trebouxiophyceae class without doubt. A phylogenic analysis of a partial sequence of 18S rRNA from this class (Figure 3B) indicates that Myrmecia might be a paraphyletic taxon as described by Friedl [62], and that this genus consisted of both lichen symbionts and freeliving species. The symbionts include M. israeliensis, M. biatorellae, M. astigmatica, Trebouxia impressa and T. asymmetrica [63], whereas the other clade comprises M. incisa

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H4301, M. incisa SAG 2007, M. bisecta, L. tirolensis and P. incisa, which are free-living species as shown in Figure 3B. A small subunit of ribosomal RNA of M. incisa H4301 has one base different in its sequence from that of M. incisa SAG 2007, as well as from M. bisecta, thus at least suggesting that M. incisa H4301 and M. incisa SAG 2007 might be a different strain of M. incisa. Seven different bases are found between M. incisa H4301 and P. incisa regardless of ambiguous bases of P. incisa 18S rRNA, whereas 9 and 12 different bases are found in comparison with P. pseudoalveolaris and P. alveolaris, respectively, implying that P. incisa differs from Parietochloris rather than from Myrmecia.

Figure 3. Strict consensus tree of two independently inferred phylogenies from Neighbor-joining (NJ) and maximum parsimony (MP) methods for rbcS (A) and 18S rRNA (B). Bootstrap values were computed independently for 1,000 re-samplings of an NJ analysis (above the line) and for 1,000 resamplings of an MP analysis (below the line), values lower than 50 are not shown. Scale indicates evolutionary distance.

Watanabe et al. [57] reclassified M. incisa into Parietochloris, due to the pyrenoids and counterclockwise basal body orientation of zoospores found by using an electron microscopy. Arachidonic Acid : Dietary Sources and General Functions, Nova Science Publishers, Incorporated, 2012. ProQuest Ebook Central,

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It is necessary to point out that the latter is a common feature of Trebouxiophyceae [62], so it seems difficult to be considered as a criterion for the identification of species in a genus. Pyrenoids can be used as a criterion for the classification of algae, and Myrmecia had been reviewed to have pyrenoids [64]. However, the poor effective investigation of pyrenoids with a light microscopy due to the usual lack of starch grains must be considered [65]. Using a transmission electron microscopy, pyrenoids, traversed by many parallel thylakoid membranes, have been observed in this study, and starch grains have been clearly observed only when cells were grown under a nitrogen stress condition (Figure 4), consistent with the reports from Merzlyak et al. [66]. Therefore, the appearance of pyrenoids was supposed to be overlooked by TschermakWoess and Plessl [67] and Reisigl [55] when they observed the cellular structure of Myrmecia only by using light microscopes. Taking the present ultrastructural observation and phylogenic analysis together as an ―integrative taxonomy‖ as suggested by Dayrat [68], it is proposed that this species be a member of Myrmecia.

Figure 4. Ultrastructural characteristics of M. incisa H4301 cells cultured in a complete BG-11 medium (A) and nitrogen-free BG-11 medium for 15 days (B) were observed by using a Transmission Electron Microscopy. Ch, chloroplast; CW, cell wall; OB, oil bodies; P, pyrenoid; SG, starch grains; Th, thylakoids.

Effects of Nitrogen Starvation on Growth and FAs in M. incisa H4301 Myrmecia incisa H4301 is characterized as an oleaginous alga, in which an amount of AA is accumulated in oil bodies (Figures 2 & 4), especially under nitrogen starvation [39]. Nitrogen is an essential element for the growth and development of algae due to its constitutional component of amino acids, nucleotides and many secondary metabolites. Thus, its deficiency would limit the biosynthesis of N-containing compounds, such as nucleic acids and proteins, and further reduce the growth rate and biomass of algae [69, 70]. In the case of nitrogen starvation, algal cells have the capacity to utilize the endogenousstored nitrogen source for fundamental metabolisms like photosynthesis to survive. To a

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certain extent, this is reflected by the growth of M. incisa H4301 during the course of nitrogen starvation. Compared to the growth in the complete BG-11 medium (1.5 g/L NaNO3, 3.0×10-2 g/L K2HPO4, 7.5×10-2 g/L MgSO4·7H2O, 3.6×10-2 g/L CaCl2·2H2O, 6.0×10-3 g/L citric acid combined with ferric ammonium citrate, 6.0×10-3 g/L disodium ethylenediaminetetraacetate, 2.0×10-2 g/L Na2CO3, trace metal solution [71]), this alga cultured in a nitrogen-free BG-11 medium, in which NaNO3 was removed and citric acid combined with ferric ammonium citrate was replaced by citric acid combined with ferric citrate, doesn’t show a significant difference while exposed to a given light intensity, despite that nitrogen starvation is not beneficial for the growth of this alga (Figure 5). Nitrogen starvation can reduce or even stop cell division due to the block of protein biosynthesis in cells [69, 70]; however, the algal biomass actually increases with the stress time of nitrogen starvation (Figure 5). It gives the impression that this alga can allocate photosynthetic products and energy originally involved in protein synthesis to N-free compounds to acclimate nitrogen starvation [72-75]. The proportion of protein in M. incisa H4301 significantly reduced (P