Microbial Carotenoids

MICROBIAL CAROTENOIDS S. LIAAEN-JENSEN AND A. G. ANDREWES1

The N orwegian Institute of Technology, Univers,j(y of Trondheim, Trondheim, N orway

CONTENTS

INTRODUCfION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 225

CHEMISTRY. • • • . . . . • . . . . . • . . • . . . . . • . . • . . . . . . . • . . . . . . • • . . . • . • . • . . . • . . . • . . . 226 General development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 226 New nomenclature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 226 New methods ........ . " .......................................... " . .. 226 New structures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 226

CHEMOTAXONOMY. • • • . . • • . • . . • • • • • • . . • • • • . . . . • • • • . . . . • • . • . . . . • • . • . . • • • . • • 229

General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 229 Photosynthetic bacteria. . . . . . .. . . .. .. .. .. .. . . . . .. . . .. . . .. . . . . .. . . . . . . ... 230 Nonphotosynthetic bacteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 230 Fungi................................................................ 230 Algae ................................................................ 231

BIOSYNTHESIS. • • • • . • • • . . . . . . • . . . . . • • • . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . • 231 General pathway ....... . ...... , ........................... " .. .. .. ..... 231 Photosynthetic bacteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 235 Nonphotosynthetic bacteria-Ct.- and Cw·carotenoids. . . . . . . . . . . . . . . . . . . . . .. 236 Nor- and apocarotenoids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

Photoinduction of carotenogenesis .. . . . ........ '. . . . . . . . . . . . . . . . . . . . . . . . . .. 239 Trisporic acid bioinduction. . . . . . . .. . . . . . . .. . . .. .. . . . . . . .. . . . . . . . . . . . . . .. 240

FUNCfION . . . • . . . . . . . • . • . " .. .. .. .. .. .. . . .. .. .. .. .. . . ..... . .. ...... ..... 242 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 Photo protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 242 The anomalous absorption effect... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 243

GENERAL OUTLOOK. • . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 244

INTRODUCTION

The biosynthesis and function of carotenoids in microorganisms was reviewed in this journal by one of us (1) in 1965. Since then, several reviews treating the biosynthesis and function of carotenoids in a general way have been presented (e.g. 2-5). In particular, a comprehensive monograph (6) covering all aspects' of carotenoids bas just appeared.

In the present paper we intend to discuss in a selective rather than comprehensive way important findings reported during the last seven years (until

1 Supported by a postdoctoral fellowship from the Royal Norwegian Council for Scientific and Industrial Research.

226 LIAAEN-JENSEN & ANDREWES

Nov. 1971) concerning the biochemistry of microbial carotenoids. Considerable progress has been made in recent years on the chemistry of microbial carotenoids, and since a chemotaxonomic picture is beginning to emerge, these topics are also included.

CHEMISTRY General development.-The number of naturally occurring carotenoids

of known structure, now counting nearly 300 (7) , has been approximately doubled during the last seven years. The main reason for this explosive development is the application of new physical and chemical methods. A number of these new carotenoids contain novel structural features. Although some carotenoids are specific to higher plants and animals the majority of naturally occurring carotenoids are encountered in microorganisms, which no doubt have demonstrated the highest ingenuity as to structural modifications of the carotenoid molecule.

New nomenclature.-Most carotenoids have been given trivial names. With the increasing number of known carotenoids the need for a systematic nomenclature has become obvious. New tentative rules recommended by IUPAC, have just been published (8, 9). Even if trivial names will still prove to be practical in biochemical papers, the semisystematic name should also be given at first mention. Introduction of new trivial names should be avoided as far as possible. Examples of the new nomenclature are given in parenthesis in Schemes 1 and 2. If not otherwise stated, trivial names are used in this paper.

New methods.-Mass spectrometry has become a routine tool in modern structural studies on carotenoids (10, 11). By this method exact molecular formulae can be determined, and the fragmentation pattern observed on electron impact provides further structural information. Since only microgram quantities are required, mass spectrometry in combination with thin-layer chromatography and electronic spectra in the visible region, now allows conclusive identification of carotenoids from microbial sources on the micro scale.

X-ray studies of several carotenoids have been performed. ,8-Carotene (I), for instance, is shown to have 6,7 (6',7') single bonds and a slightly Sbent polyene chain (12) .

X-ray studies of suitable derivatives are also the prerequisite for determination of absolute configuration of carotenoids containing asymmetric carbon atoms. Optical rotatory dispersion (ORD) or circular dichroism (CD) spectra, however, are the major tools for stereochemical correlation. The absolute configuration of several of the more common carotenoids have been established in recent years (13, 14), exemplified by fucoxanthin (II). The RIS convention is used to denote absolute stereochemistry (15).

New structures.-Traditionally, carotenoids were considered as C40 (skeletal) compounds or apocarotenoids (with less than 40 carbon atoms in the

MICROBIAL CAROTENOIDS /3-Carotene (/3,/3-carotene);

Fucoxanthin [(3S,5R,6S,3'S,5'R, 6'R)-5,6-epoxy-3.3',5'-trihydroxy-6',7'-didehydro-5, 6,7,8,5',6' -hexahydrO-,B,,B-caroten-8-one 3' -acetate];

HO . ....:><,. A-1 II

HO I ··OCOCHa Decaprenoxanthin [2,2' obis ( 4-hydroxy-3-methyl -2-buten y I) -e,e-carotene];

Bacterioruberin [2,2'-bis(3-hydroxy-3-methylbutyl) -3,4,3',4'-tetradehydro-I,2,1',2'tetrahydro-.p,.p·carotene-l,l' -diol];

OH MyxoxanthophyIl; myxol 2' -rhamnoside [2' -(,B-L-rhamnopyranosyloxy)-3' ,4' -dide

hydro-I' ,2' -dihydro-tl,y,-carotene-3, l' -diol]:

Rhodopinal D-glucoside [13-cis-l-(,8-4 glucopyranosyloxy) -1 ,2 -dihydro-", ,,,,-caroten-20-al]:

SCHEME 1.

skeleton) derived therefrom. Carotenoids with C45- and C50-skeletons in which extra isoprenoid C5-units are formally added to 2,2'-position (for numbering of the carbon skeleton see structure I, Scheme 1), therefore represent novel structures. Four representatives of the C%-series and 13 of the

Siphonaxanthin (3,19,3' -trihydroxy-7 ,8-dibydro-,9,e-caroten-8-one):

Diadinoxanthin (5,6-epoxy-7',8'-didehydro-5,6-dihydro-,B,,B-carotene-3 ,3' -diol) :

Phillipsiaxanthin (1,1' -dihydroxy-3 ,4,3' ,4' -tetradehydro-l ,2, 1',2' -tetrahydro-"."".,-carotene-2,2'-dione)R=H IX

2,2'-Diketospirilloxanthin (1, 1'-dimethoxy-3,4,3',4'-tetradehydro-l,2,I',2'-tetrahydroy"y,-carotene-2,2'-dione)R=CHa X:

RO 3,3'-Dihydroxyisorenieratene (cp,cp-carotene-3 ,3' -diol) :

_ :'p,'Y-Carotene" (5,18-didehydro-5,6-dihydro-,B,,B-carotene):

Peridinin (5' ,6'-epoxy-3,5,3'-trihydroxy-6, 7 -didehydro-5 ,6,5',6' -tetrahydro-lO, 11,20-trinor-,8,,8-caroten-19', 11' -olide 3-acetate) :

�-�� CH3COO�OH

SCHEME 2.

C50-series have been characterized (7, 16). Two typical representatives decaprenoxanthin (III, 17) and bacterioruberin (IV, 18) are depicted in Scheme 1.

Some sixteen glycosidic carotenoids have been identified in recent years (7, 16). The rhamnosid myxoxanthophyll (V, 19) and the glucoside rhodopinal glucoside (VI, 20) are given in Scheme 1 as typical representatives. Tertiary glycosides are rare in nature, except in the carotenoid field (cf VI).

Oxidized in-chain methyl groups is another new structural feature. Carot-

MICROBIAL CAROTENOIDS 229 enoids of the rhodopinaI series (e.g. VI) have a cross-conjugated aldehyde group in the 20-position, which results in cis-configuration of the adjacent double bond (21)" . In siphonaxanthin (VII, Scheme 2) the 19-methyl group has formally suffered oxidation (22), a feature in common with loroxanthin (23) and vaucheriaxanthin (24).

A number of bicyclic carotenoids with carbon-carbon triple bonds in 7,8 (7',8') position have been demonstrated (25). As an example of such acety· lenic carotenoids diadinoxanthin (VIII, 26) is given.

Important representatives of allenic carotenoids are fucoxanthin (II, 27, 28) and peridinin (XIII, 29).

The known number of carotenoids with tertiary methoxy groups like 2,2'diketospirilloxanthin (X, 30) has increased, and carotenoids with tertiary ester groups in the corresponding position have been encountered, e.g. phillipsiaxanthin (IX, 31) diester.

Additional aromatic carotenoids have been found (32-35) and phenolic carotenoids encountered for the first time, namely, 3-hydroxy- and 3,3'-dihydroxyisorenieratene (XI, 36).

Even carotenes have revealed new structural features. ,B,y-Carotene (XII, 37) with an exocyclic methylene group was the first known carotene with yionone-type ring structure.

New apocarotenoids (38) and structurally more interesting norcarotenoids are described (7, 16). In norcarotenoids, carbon atoms have been formally expelled from the skelton without cleavage of the molecule. Peridinin (XIII, C37-skeleton) also accommodates another new structural element, the lactone ring (29).

As seen from these examples the structural variations in naturally occurring carotenoids are numerous. The color shades, reflecting the length of the chromophoric system, range from the colorless phytoene to yenow, orange, red, and even blue representatives such as the derivative violerythrin (39).

A further treatment of the chemistry of new microbial carotenoids is beyond the scope of this survey and the reader is referred to an extensive compilation (6) and the original references cited therein.

CHEMOTAXONOMY General.-Many factors contribute to biological individualism. Chemo

taxonomy, based on the distribution and structures of selected secondary metabolites, is frequently a useful tool for classification in combination with other criteria. The method has found widest application for higher plants, but the distinction between green (Chlorobacteriaceae) and purple (Athiorhodaceae and Thiorhodaceae) photosynthetic bacteria, for instance, was based on the pigments even at a time when little was known about each individual pigment.

Since the structural variations of carotenoids gradually have proved to be numerous, the usefulness of carotenoids as chemotaxonomic markers has incre<lse�. IIowever, s\lch considerations require extensive anQ. reliable analy-

ses, so far available for only a limited number of species. Ideally, biosynthetic pathways and not only terminal products should be considered.

Photosynthetic bacteria.-The latest compilation of carotenoids in photosynthetic bacteria dates back to 1963 (40), although the topic was included in Pfennig's authoritative treatment on photosynthetic bacteria four years a.go (41). Original papers covering Chlorobacteriaceae (42) and several Thiorhodaceae spp. (43) have since been published. Following is a brief generalization based on the numerous papers in the field:

Methoxylated carotenoids are not encountered outside the photosynthe:tic bacteria and are peculiar to certain Athiorhodaceae and Thiorhodaceae spp. Aliphatic carotenoids with tertiary hydroxy groups in the 1-position, occasionally carrying conjugated keto groups in the 2-position, or cross-conjugated aldehyde groups in the 20-position, are frequently encountered in photosynthetic bacteria.

A monocyclic aryl carotene, chlorobactene (44) with 1,2,5-trimethylphenyl end group, is specific for Chlorobacteriaceae, whereas aryl carotenoids of okenone (34) type with 1,2,3-trimethylphenyI end group are found in certain Thiorhodaceae spp.

Around 60 different carotenoids are encountered in photosynthetic bacteria. Among these are carotenes with the novel 1,2-dihydro feature (45).

An unknown material containing photosynthetic bacteria may be readily identified in many cases to family and species level from its carotenoid composition.

Nonphotosynthetic bacteria.-Such bacteria have been less systematically studied. However, the following conclusions seem justified: With two exceptions, C"o- and Coo-carotenoids are so far restricted to nonphotosynthetic, Gram-positive aerobic bacteria with guanine plus cytosine ratio above 70 percent. Gram-negative Halobacterium spp. are C50-carotenoid, e.g. bacteIioruberin (IV) producers, but it is known that halobacteria have an unusual cell wall more in common with Gram-positive bacteria (46).

Glycosidic carotenoids are encountered in various nonphotosynthetic bacteria like Mycobacterium phlei (47), Sarcina lutea (48), and Corynebacterium erythrogenes (49). However, glycosidic carotenoids of different structure are also found in photosynthetic bacteria (20) and blue-green algae (19, 50,51).

Flexibacteria contain carotenoids of structural type intermediate between those of other bacteria and blue-green algae (52), which might reflect the evolutionary history of gliding microbes.

Fungi.-For fungi, again, only scattered information is available. Typical yeast carotenoids are considered to be those of torulene, torularhodin, and neurosporaxanthin type (6, 53, 54).

The only known source of phenolic carotenoids is Streptomyces mediola-

MICROBIAL CAROTENOIDS 231 nii (36). Aryl carotenoids are also found in photosynthetic bacteria (34,44) and Mycobacterium sp. (55).

Tertiary carotenol esters, structurally related to the methyl ethers of photosynthetic bacteria, are encountered in macroscopic fungi (31,56), and carotenes with terminal methylene groups have thus far only been encountered in two macroscopic fungi and aphids (16, 37, 57).

AIgae.-Microscopic representatives are found within all algal classes and a distinction between micro and macro forms are not made in the following. The characteristic structural elements of common carotenoids encountered in algae are summarized in Table 1. It is pointed out that sufficient data are not yet available for all algal classes to justify such generalizations.

Algal carotenoids were recently thoroughly reviewed by Goodwin (58) who proposed an evolutionary scheme based on carotenoid composition. His scheme is based on the evolution of the following specific enzymes: a-cyclase (cf our Table 1, column A, R = H): f3-cyc1ase (column B, R = H); a- or 13-carotene hydroxylase (columns A and B, R = OH); exoxidase (column C) ; and violaxanthin isomerase postulated to caUSe transformation to allene (column D) according to reaction a in Scheme 3. Triple bonds (column E) were tentatively formulated as arising by direct dehydrogenation of carbon-carbon double bonds, and the origin of the 8-keto structural element (column F) typical of fucoxanthin and siphonein by reaction b in Scheme 3. Triple bond formation according to reaction c (Scheme 3) is one other alternative with in vitro precedence (59) .

Consideration of carotenoid structures undoubtedly supports the idea that blue-green algae (Cyanophyceae) represent the lowest level in the evolution of algae. Until more is known about the biosynthetic reactions leading to the ultimate carotenoids in algae we feel there is not yet evidence for further detailed interpretations. However, a close relationship between Bacillariophyceae, Dinophyceae, Xanthophyceae, and Cryptophyceae, all producing acetylenic carotenoids, seems likely. Using fucoxanthin (II), whose structure incorporates several characteristic structural elements, as chemotaxonomic marker, a close relationship between Phaeophyceae, Chrysophyceae, and Bacillariophyceae is indicated. The recent complex structure of peridinin (XIII), structurally related to fucoxanthin (II) but more elaborated by nature, makes peridinin a chematoxonomically important carotenoid.

BIOSYNTHESIS General pathway.-The advances made in the studies of carotenoids have

on the whole not matched the gains made in the chemistry of these pigments. Furthermore, most studies on the biosynthetic aspects have been in plant systems and it is from both plant and microbial data that we shall present the current state of carotenoid biosynthesis.

Geranylgeranyl pyrophosphate (GGPP), synthesized from mevalonic acid (MVA) by the normal terpenoid pathway, has now been firmly e!ltab�

TABLE 1. CHARACTERISTIC STRUCTURAL ELEMENTS OF COMMON CAROTENOIDS IN ALGAE

A 13 C D E F G H K

]X" J5c" Yo X&

R� ALGAL CLASS

R � R X 'e--C=C C=C S-keto IS-ox. carot.

Rhodophyceae + + ? Rhapidophyceae + + ? Chlorophyceae (+) + + + C+) C+) (+) Phaeophyceae + + + + Chrysophyceae + + + + + + Bacillariophyceae + + + + + Dinophyceae + + + + + + Xanthop hyceae + + + + Ciltophyceae + + + Eug enophyceae + + + + Cyanophyceae + +b +

& R=RH or OH. b As furanoid oxide. ( ) Not common.

Mono- Glyco-cyclic sides

N u.l N

� � .!., tl1 Z CJl

� p,o :> Z '=' � � �

MICROBIAL CAROTENOIDS 233

b. CX .. .-l

· +H,O

[co;.. ] �R - --

ci.l.· -H2O cx .. .-l·

C. -Io:0H

SCHEME 3.

lished as the immediate precursor to phytoene, the first C40-carotene. The possible role of lycopersene has largely been discounted on the basis of numerous experiments which failed to demonstrate any evidence for its existence (60-64). Conversion of GGPP into phytene by a variety of preparations has been reported: Goodwin and co-workers (65), using "nonaqueous" bean leaf chloroplasts have converted GGPP into phytoene as have Lee & Chichester (66) using a homogenate of Phycomyces blakesleanus, and Shaw et al (67) using a partially purified tomato preparation.

Many other studies with intact systems and cell-free preparations have shown the incorporation of MV A, isopentenyl pyrophosphate (IPP), and farnesyl pyrophosphate into phytene and other carotenes (4, 68-73). In addition, Goodwin and his co-workers (73) have defined the stereochemical course of the reactions from MV A to phytoene using specific doubly labeled MVA precursors. Tefft et al (74) , working with Rhodotorula rubra. have demonstrated the stereospecific labeling at the acyclic C-l' position in torularhodin. Using (2_HC) MVA, these authors showed that the carboxyl group contained the label, the methyl group being inactive (see Scheme 4) .

Evidence from enzymatic studies has accumulated to define the pathway from phytoene to lycopene in plants, bacteria, and fungi. The direct conversion of labeled phytoene into the less saturated acyclic carotenes has been reported: Suzue (75) has claimed incorporation into 8-carotene by extracts of Staphylococcus aureus; Beeler & Porter (76) reported conversion to phytofluene by a tomato chloroplast preparation; Kushwaha et al (77) stated

�o CHa H H '. \ HOOC 2 OH (2-"C)MVA

Torularhodin

SCHEME 4.

conversion into cis- and trans-phytofluene, zeta-carotene, neurosporene, and lycopene by a soluble tomato enzyme preparation, and Subbarayan et al (78) reported conversion into phytofluene and lycopene by a spinach chloroplast enzyme system.

From the evidence that plant phytoene has a central cis configuration (79, 80) and natural zeta-carotene is trans, Kushwaha et al (77) have proposed the following more detailed sequence for dehydrogenation of phytoene to ly. copene in plants which is based on the incorporation of phytoene into both cis- and trans-phytofluene by tomato enzyme preparations:

cis-phytoene ...., cis-phytofluene...., trans-phytofluene

! lycopene � neurosporene � zeta-carotene

In many of the enzymatic conversions cited, cofactor requirements for the reactions were reported (61, 65, 66, 77, 78) . It is generally agreed that GGPP can be converted into phytoene with Mg2+ or Mn2+ and a SH protector as cofactors. However, the details of subsequent reactions are confusing. Lee & Chichester (66) reported no nicotine adenine diphosphate (NADP) requirement for conversion of GGPP into phytoene or lycopene while Porter's group (77) have claimed that NADP is required to convert phytoene to phytofluene and flavine adenine diphosphate (FAD) for further desaturations.

Clearly, a hydrogen acceptor must be involved in the desaturation reactions, but the intimate step requirements have still to be verified, using puri. fied enzyme systems. It is still not known whether the stepwise conversion of phytoene to the less saturated carotenes is effected by individual enzymes or by an enzyme complex. In the former case a carrier requirement may be necessary.

MICROBIAL CAROTENOIDS 235 Direct evidence has been reported for cyclization of isotopically labeled

lycopene into cyclic carotenes by chloroplasts (78, 81-84), by tomato plastids (77), and by soluble enzyme systems (77, 78), Other circumstantial evidence supports the hypothesis that cyclization can occur at the lycopene level. In Mycobacterium spp., nicotine inhibits (3-carotene synthesis and lyeopene accumulates (85), an effect also observed with Flavobacterium spp. and Phycomyces blakesleeanus (73). When nicotine is washed out of the cultures, ,8-carotene is formed at the expense of lycopene. Similar inhibition studies on pumpkin cotyledons (86) and fruit (87) lead to the same conclusion.

The occurrence of a- and ,8-zeacarotene makes it clear that cyclization can occur at the neurosporene level. However, no direct conversion of neurosporene to the cyclic carotenes has been reported. Again, inhibition studies similar to those mentioned for lycopene support neurosporene as the precursor to cyclic carotenoids in some systems (88-91) .

Labeling experiments by Goodwin's group have established that a- (E- by the new nomenclature ) and {3-rings common to carotenoids are formed independently although a common carbonium ion intermediate is proposed (92) which, incidentally, can accommodate the rccent finding of '}'-type rings in carotenes (37). Hydrogen atoms from (2_14C,4-R-43H) MVA incorporated into the 6,6' positions of acyclic carotenes are lost in the formation of (3-carotene (92). The hydrogen atom at C-6' of a-carotene would be unlabeled if this compound arose by isomerization of ,8-carotene. Experiments revealed that tritium in pOSition C-6' of a-carotene, synthesized from carrots and tomatos, is retained, which showed that ,8-carotene is not an intermediate in acarotene formation (see Scheme 5). Other experiments with (2-14C,2-3H) MV A which would label the hydrogen atoms at C-4 (92) have shown that one labeled hydrogen is lost in the formation of a-carotene and both retained in this position in (3-carotene, which indicated that ,8-carotene is not formed from a-carotene.

New evidence on trisporic acid biosynthesis (73) suggests that a more complex cyclization picture may ultimately emerge.

Little is known of the biosynthesis of xanthophylls although strong circumstantial evidence points to the introduction of oxygen at a late stage of the biosynthetic process (93, 93b, 102) . Recently, Yamamoto et al (94-96) have reported on the source of oxygen in the xanthophylls of Chlorella and Phaseolius lunatus and some work on the interconversion of xanthophylls has been reported (97-99).

Photosynthetic bacteria.-The characteristic structural features of carotenoids encountered in photosynthetic bacteria are dealt with in the chemotaxonomy section. According to recent findings, the prelycopene pathway in Athiorhodaceae differs from that of higher plants. The divergence occurs in the dehydrogenation scheme subsequent to phytofluene where, in Rhodospirillum rubrum and Rhodopseudomonas spheroides, 7,8,1l,12-tetrahydrolyco-

�,.. -H.6/ Ul..

�_ /'" ,B.ring � " 6

" � Cc---a.ring

SCHEMES.

pene is formed in place of zeta-carotene (100). The isolation of 11', 12'-dihydrospheroidene from R. rubrum grown in the presence of diphenylamine was taken by Davies (100) to support the transformations of 7,8,1 1, 1 2-tetrahydrolycopene to spheroidene given in Scheme 6. The isolation of 3,4,1l',12'-tetrahydrospheroidene and 3.4-dihydrospheroidene from large-scale normal cultures (100) supports the proposal that also in R. rubrum alternative path· ways to spirilloxanthin may operate alongside the so-called normal spirillox· anthin pathway previously established (1, 101). The hypothetic intermediate demethylated sphcroidene (107), is now replaced by 3,4-dihydrospheroidene assuming that methylation precedes the dehydrogenation step. These and other (16,20) new features are all included in Scheme 6 to depict the overall biosynthetic pathway operating in Athiorhodaceae.

The biosynthesis of the aromatic carotenoid okenone (103) from the purple sulfur bacterium Chromatium okenii remains unsolved although a mechanism for its synthesis from a common ,B-endgroup has been advanced (103). The recent discovery of l'-methoxy-l',2'-dihydro-,B,t/r-caroten-4'-one (new nomenclature) as a minor component in Thiothece gelatinosa (35), suggests that the introduction of the keto function precedes aromatization although the mechanism for introducing a keto function into an obligate anaerobe is as yet unexplained.

Recent publications on the structures of the rhodopinal series of carotenoids (104) suggests that these pigments arise by in-chain oxidation of the. basic lycopene unit. Again, the mechanism of the anaerobic oxidation is unknown.

Nonphotosynthetic bacteria-C45- and C50-carotenoids .-Nonphot()synthetic bacteria are the only known source of the "homo" carotenoids-carotenoids with 45 or 50 carbon skeletons (cf section on chemistry above) .

Flavobacterium dehydrogenans has yielded two C50-carotenoids [including decaprenoxanthin (III)] and three C45-pigments whose structures are

Lycopenal \<s,o

Rhodopinal

P.hytoene OH-7 • S ,l1,12-Te trabydrolycopene

a-carotene Phytofluene +H20 ,,11,11' ,12'-'fetrahydrospheroidene "2H y/ . j+CH2

_ �m }� ... _______ __ ___ (L;yc openol ) 7 t8Jll.12�Tetrahydrolycopene 11' ,12'-Dibydroapheroidene

-2H ...................... t-2H +Fr a 4 ____________ Rhadopinol .... ..... ..... _ Neur:»eporene 2 Chloroxanthin -2H

Rhodopinalgl'leo-aide ',,�o " ,,_ t2H 1-2H

-_..... . Lycopene 3,l:!-DihYdroepheroidene ,.0 +CH2 ................ J+H20 ,,�+Cy<"2H

Methoxylycopenal ____________ (Methoxylycopene) _a.-____ ..::. Rhodopin S-pheroidene -... 0 • +H20,+CH2 .... :r J-2H _ -2».........

......... �+H20 + 0, -2H

Tetrabydroapirilloxantl1.ina1 ... ----- Tetrabydro19-pul.J.loxanthi,9 ".-;", 3 ,ll-Dehydro-rhodopin ':!' .... ;; / OH-Spheroidene ---'---_ 1 +2CH2·-IiR ,/'" ",/ �+CH2 .... " .....

RHODOPINAL � SERIBS

Di�OH-lycOpene"""" ,,�/ Anhydro-rhodOvibr:in ,.,

'" !+H20 Rhodopinglucoside # Rhodovibrin

�-2H +0, -2H OH-Spirilloxanthirt -------------'-------_ �+CH2 +0) -28 Spirilloxanthin -------______ -'--_____ _

NORMAL SPIRILLOXAN'lHIN

rATlIWAY

SCHEME 6.

ALTERNATIVE SPIRILLOXANTHIN • PA'I'HWAYS

Spheroidenone j+H20

OH-Sphero:tdenone

2-keto-OH-apirilloxanthin

I<CH2 (2-keto-apir111oxanthin) �+o, -2H

2,2 '-Diketo:spirilloxanthin

KE'TO SERIES

@ � �

tv r...l -..,J

238 LIAAEN-JENSEN & ANDREWES A...-.+ ""�R

H c'o-Precursor

�R - --+ (0)

SCHEME 7.

c..·Carotenoid

now known (17,105) . Analysis of the minor pigments produced under various cultural conditions has shown that the normal acyclic C40-carotenes are synthesized by this bacterium (46) . Some evidence for 7,8,1l,12-tetrahydrolycopene was obtained under conditions of nutritional imbalance. A biosynthetic scheme accounting for all the pigments has been advanced (46). In this scheme, the C45-carotenoids arise from a C4o-acyclic precursor by the mechanism advanced in Scheme 7.

From Halobacterium salinarium, Kelly et al (1S) have elucidated the structures of bacteriorubrin (IV) and two related Cso-carotenoids. These "homo" carotenoids differ from those of F. dehydrogenans in that they are acyclic and can arise by the mechanism given in Scheme S.

Corynebacterium poinsettiae is the source of one C45-and four Cso-carotenoids of which two have isoprenyl groups attached to f3-rings (106). The postulated pathway to the (3-ring is similar to that depicted for F. dehydrogenans except that during cyc1ization it is the C-6 proton which is lost.

N or- and apocarotenoids.-The recent publication (51) on the structure of peridinin (XIII) is further demonstration of the biological ingenuity associated with carotenoid synthesis in microorganisms. Isolated as the principal pigment of dinoflagellates, peridinin (XIII) has been shown to have one allenic end typical of fucoxanthin (II) or unesterified neoxanthin and an epoxide end group characteristic of violaxanthin, neoxanthin and fucoxanthin (II) . A structural feature unique to carotenoids is a lactone ring situated inchain which forms a part of the chromophore. A hypothetical pathway (51) for the formation of peridinin is shown in Scheme 9. Assuming an isoprenoid C40-precursor, the required expulsion of three carbon atoms from the polyene chain to account for the C3r-skeleton is noteworthy.

From a yellow halophilic coccus, Aasen et al (107) have isolated the tertiary glycoside methyl- l-hexosyl- l ,2-dihydro-3 ,4-didehydro-apo-S' -lycopenate. Cultural studies indicate that the precursor may be the corresponding glycosidic caroteno!. Under conditions of limited aeration the cultures syn-

Jv.. + �R O H R -2H . '" R 9 �OH HO�OH

- 1 +ibo ",I

SCHEME 8.

MICROBIAL CAROTENOIDS

0" 'lc-o

" " "'v O�""R

ij 13' 14' - R-C-C:CH 8

15 12' 10' S'

YioAC OH

Hypothetic biosynthetic formation of peridinin.

SCHEME 9.

thesize oxygenated apocarotenoids as minor components, whereas with excess oxygen supply they were the major pigments. This observation may imply that oxygen plays a direct role in the synthesis of the apocarotenoids.

Apocarotenals have been recently identified from the purple sulfur bacterium Thiothece gelatinosa, the major pigment of which is okenone (35). The carotenals, which have a 1,2,3-trimethyl-substituted aromatic ring characteristic of okenone, are probably metabolic products of okenone and suggests that the degradation of okenone is initiated at the acyclic end.

Photoinduction of carotenogenesis.-Carotenoid synthesis in a number of nonphotosynthetic bacteria and fungi occurs only after a short exposure to both light and oxygen. This phenomenon has been investigated in a number of instances and suggestions as to the receptor pigment and bioprocesses involved have been advanced. The action spectrum for Neurospora crassa could be accomodated by either a carotenoid or flavin as the receptor (108) while, in Mycobacterium marinum, the action spectrum corresponded to a porphyrin (109) . Rilling (110) has suggested that flavin is the receptor in another Mycobacterium sp.

The function of oxygen in fungi has been assigned as an electron acceptor

to keep the photoreceptor in the proper oxidation state (111). Rilling (109) has suggested that in Mycobacterium spp. oxygen acts directly in the generation of a new compound which then operates as a chemical inducer of carotenoid enzyme synthesis.

Inhibition of carotenoid synthesis after photoinduction by the potent inhibitors cploroamphenicol and actidione (112, 113) supports the view that enzyme synthesis is involved.

Trisporic acid bioinduction.-Recent evidence has come to light explaining, at least in part, the observation that trisporic acjd can stimulate carotenogenesis in the (-) strain of Blakeslea trispora and other fungi (114, 115). A second relationship between trisporic acid and carotenoids noted by Heisenberg & Cerda-Olmedo (116) is that a block in carotenogenesis in mutant

strains of Phycomyces resulted in abortive zygote formation. Studies by Bu'Lock and co-workers (117) on the biosynthesis of trisporic

acid (XIV) in B. trispora have shown that �-carotene (I) can be converted to trisporic acid but not the reverse (118). Diphenylamine inhibition which blocks carotenogenesis also blocks trisporic acid formation (117). Experiments with labeled retinyl acetate showed conversion to trisporic acid and the corresponding alcohol trisporol (119). From these and other data, a pathway for trisporic acid formation in fungi from �-carotene was formulated (119):

�-carotene -+ retinol -+ trisporol -+ trisporic acid Thus, a block in carotenogenesis inhibiting �-carotene would also inhibit trisporic acid formation. Since the latter compound controls gamogenesis (120), the incomplete development of sexual relations in Phycomyces is adequately explained.

The precise mechanism for trisporic acid induction of carotenogenesis is not known but since its effect is inhibited by actidione, a specific inhibitor of protein synthesis, trisporic acid may derepress a gene regulating the synthesis of a specific enzyme concerned with carotenogenesis (121).

Studies by Bu'Lock's and Snatzke's groups (122) on the absolute configuration of trisporic acid (XIV) may be pertinent in understanding the cyclization mechanism of carotenoids. Using labeled (2_HC) MVA, the absolute configuration of trisporic acid at C-l (IS) was determined. Moreover, the label from (2-14C) MVA was introduced into the methyl group at C-l. Since trisporic acid arises from �-carotene (I) the same situation must hold for �carotene (I). Assuming that the cyclization of �-carotene proceeds through folding of a chair form-analogous with other terpenoids-then the absolute stereochemistry of cyc1ization of �-carotene must be that indicated in Scheme 10, being followed by loss of axial H at C-6. However, loss of axial H at C-4 would result in an enantiomer (6-S) of natural (+ )-a-carotene (123). Boat folding of the acyclic precursor could give rise to the correctly labeled H-carotene and to the correct optical isomer of a-carotene, if the branching point in the biosynthesis of the two ring types is at the caroonium ion interml�diate

:t: o :r;

MICROBIAL CAROTENOIDS

:r; E o 0

b\ � c: \ U � \ " .. a , ...:.. � '" 8 .! . '" <rt -

:t: " :t:

u o .� ,::

~ '" t

.... :i:. I

as previously proposed (92). Alternatively the hypothesis of a common carbonium ion must be abandoned in favor of a divergence in the pathway to aand (3-rings at an earlier stage.

FUNCTION

General.-It is not surprising that, given the ubiquitous nature of carotenoids, a large variety of functions have been, at one time or another, attributed to these pigments. A recent publication has commented extensively on virtually all of these proposals (124), and exhaustive treatments on specific functions are also available (125-128). Carotenoids have been implicated in photoprotection to prevent chlorophyll (CHL) bleaching and membrane enzymes against photodynamic destruction, in photosynthesis as accessory pigments, in O2 evolution and transport, as cofactors in photosynthetic reactions, in phototropism, phototaxis, and photoreception. Our treatment is restricted to areas in which important contributions are made recently.

Photoprotection.-The most firmly substantiated function of carotenoids first advanced by Stanier, is that they can protect cells and tissues against lethal photodynamic damage which is catalyzed by CHL or bacteriochlorophyll (BCHL) (129-132). Fujimori & Livingston (133) demonstrated that carotenes were able to quench harmful triplet CHL and, until recently, the following mechanism advanced by Schenck (134) has been used to explain photosensitized oxidations:

hI' Sen -t ISen

Sen-02 + A -t A02 + Sen Here the sensitizer (Sen) oxygen complex reacts with the acceptor A to produce photodamage.

Simultaneous publications in 1964 presented evidence that 102 can carry out reactions identical with photosensitized oxidations (135-136) and, in the same year, Foote & Wexler (137) suggested that 102 was the intermediate in photochemical oxidations. Kinetic studies (138), using f3-carotene as inhibitor of photochemical reactions, lead to the proposal that there was a direct energy transfer from 102 to f3-carotene to yield triplet state carotenoid eCar) plus ground state (triplet) oxygen. There is some evidence that the triplet energy level of (3-carotene is low (139) and may be in the required range of '02 (22 kcal).

Subsequent experiments by Foote and co-workers (140) showed that the protective action of carotenes in photosensitized oxidations was a direct function of the number of conjugated double bonds, which supports earlier

MICROBIAL CAROTENOIDS 243 observations (141, 142). The minimum number of conjugated double bonds required for effective quenching of '02 is nine. Another important observation by Foote's group (143) was that the quenching by carotenoids in vitro is not an oxidative process; in fact, only one in a thousand carotenoid molecules involved in 102 quenching undergoes chemical oxidation. Studies on model trienes (144, 145) have shown that this slow irreversible oxidation can lead to allenic products similar to those functions found in fucoxanthin and neoxanthin. A protective scheme advanced by Foote (143, 143b) which considers his and other observations is given in Scheme 11.

CHL hv--+ JCHi �o:---+ PhotoSY�::S:

r CAR · O2 other acceptor

quenching (--- 3CHL ----+ 102 --+ damage

CA�/ 1 (10-3) CAR

802 + CAR CAR. OX. SCHEME 11.

In this scheme one in 104 molecules of lCHL goes to lethal 3CHL. Of the 3CHL some, through a diffusion-controlled process (146), may be quenched by carotene (process advanced by Fujimori and Livingston, 13 3). However, this reaction competes with the similarly controlled quenching liy O2 and, since both occur at the same rate, the carotenoids could only protect if their local concentration greatly exceeded that of O2, The remaining 3CHL reacts with O2 producing '02 which can react with CHL or another acceptor to produce photodamage. It can also be quenched by carotene; of the quenching reactions, 1 in 103 would lead to oxygenated carotenes.

The anomalous absorption effect.-Under conditions of illuminating green algae or introducing O2 into a culture of photosynthetic bacteria, a change in the absorption spectrum occurs. The change is characterized by an increase in absorbancy at 510-520 nm and has been generally attributed to carotenoid pigments but the relationship is not clear.

The suggestion that the observed spectral change is due to the formation of a metastable carotenoid pigment (139) has received support from a number of workers (147-149). This metastable state, presumably triplet carotenoid, can arise according to the mechanism advanced by Foote (139). Wolff and Witt (150, 151) have developed this theme into a scheme which they call the "valve reaction" for draining off excess radiant energy.

Another suggestion of recent origin is that the spectral effect is a reflection of a conformational change in thc membranes containing carotenoids (152). Both photosynthetic phosphorylation (153, 154) and the develop-

ment of an electrical field across the cell membrane ( 155, 156) have been advanced to explain the conformational changes.

GENERAL OUTLOOK In many respects the advances made in the studies of carotenoids OVf:r the

last seven years have been spectacular particularly, as mentioned, ill the chemistry of these pigments. In the next few years it is expected that solutions to some of the more sophisticated questions concerning the biochemistry of carotenoids will receive attention. For example, the reaction mechanism and cofactor requirements for the conversion of phytoene to the less saturated carotenes are not known; also the major immediate precursor to the cyclic carotenes has not been conclusively established in any system. The whole area of xanthophyll formation is virtually wide open and although the formation of oxygenated carotenoids presumably is an enzymatic process, xanthophyll formation must be further studied. In the latter respect, it is interesting to see whether the ideas advanced by Foote and others ultimately play an important role.

In the area of stereochemistry the absolute configuration of the C45- and C50-carotenoids is not yet known. Although no diastereomers of the same carotenoid isolated from different sources has yet been found this point should be pursued. Increased understanding of ORD and CD spectra of carotenoids should facilitate further stereochemical considerations.

The well-known correlation between vitamin A and (3-carotene and between trisporic acid and (3-carotene should b� sufficient incentive to encourage a systematic study of the metabolism of carotenoids to determine if other biologically important compounds such as abscisic acid are derived from carotenoids.

MICROBIAL CAROTENOIDS 245

LITERATURE CITED

1. Liaaen-Jensen, S. 1965. Ann. Rev. Microbiol. 1 9 : 1 63

2. Chichester, C. 0., 1967. Pure Appl. Chem. 14:215

3 . Goodwin, T. W. 1969. Pure Appl. Chem. 20 :483

4. Porter, J. W. 1 969. Pure Appl. Chem. 20: 449

5. Krinsky, N. I. 1 968. Photophysiology, 3 : 21 3, ed. A. C. Giese. New York: Academic

6. Isler, O. Ed. 1971. Carotenoids. Basel : Birkhiiuser

7. Straub, O. 1 971. Carotenoids, Chap. XII, ed. O. Isler. Basel: Birkhiiuser

8. Isler, O. Ed. 1 97 1 . Carotenoids, Appendix. Basel : Birkhiiuser

9. IUPAC Tentative Rules for the Nomenclature of Carotenoids. 1 972. Biochemistry. In press

10. Vetter, W., Englert, G., Rigassi, N., Schwieter, U. 1971. Carotenoids, Chap. IV, ed. O. Isler. Basel : Birkhauser

1 1 . Eozell, C. R. 1969. Pure Appl. Chem. 20:497

12. Sterling, C. 1964. Acta Crystallogr. 17 : 1224

13. Weedon, B. C. L. 1971. Carotenoids, Chap. V, ed. O. Isler. Basel : Birkhiiuser

14. Buchecker, R., Hamm. P., Eugster. C. H. 197 1 . Chimia 25: 192

15. Cahn, R. S., Ingold, C. K., Prelog, V. 1956. Experientia 12: 8 1

16. Liaaen-Jensen, S . 1 971. Caroteno ids, Chap. III, ed. O. Isler. Basel: Birkhauser

17. Liaaen-Jensen, S., Hertzberg, S. Weeks. O. B., Schwieter, U. 1 968. Acta Chem. Scand. 22: 1 1 7 1

18. Kelly, M., Norgard, S., LiaaenJensen, S. 1 970. Acta Chem. Scand. 24 :2169

19. Hertzberg, S., Liaaen-Jensen, S., 1969. Phytochemistry 8 : 1259

20. Schmidt, K., Francis, G. W., Liaaen-Jensen, S. 1971. Acta Chem. Scand. 25 : 2476

2 1. Aasen, A. J., Liaaen-Jensen, S. 1 967. Acta Chem. Scand. 21 : 2 1 8 5

22. Walton, T. J . , Britton, G. , Goodwin, T. W., Diner, B., Moshier, S. 1 970. Phytochemistry, 9 : 2545

23. Aitzetmiiller, K., Strain, H. H.,

Svec, W. A., Grandolfo, M., Katz, J. J., 1 969. Phytochemistry 8 : 1761

24. Strain, H. H., Svec, W. A., Aitzetmiiller, K., Grandolfo, M., Katz, J. J., 1 968. Phytochemistry 7 : 1417

25. Weedon, B. C. L. 1 970. Rev. Pure Appl. Chem. 20: 5 1

26. Aitzetmiiller, K., Svec, W . A., Katz, J. J., Strain, H. H. 1 968. Chem. Commun. 32

27. Jensen, A. 1 966. Norw. Inst. Seaweed Res. Rep. No. 31, Trondheim : Tapir

28. BOimett, R. et al 1 969. 1. Chem. Soc. C 429

29. Strain, H. H. et al 1 97 1 . J. Am. Chem. Soc. 93 : 1823

30. Jackman, L. M., Liaaen-Jensen, S. 1 964. Acta Chem. Scand. 1 8 : 1403

3 1 . Arpin, N., Liaaen-Jensen, S. 1967. Bull. Soc. Chim. Bioi. 49:527

32. Liaaen-Jensen, S. 1 966. Biochemistry of Cloroplasts, p. 437, ed. T. W. Goodwin. London: Academic

33. Liaaen-Jensen, S. 1965. Acta Chem. Scand. 1 9 : 1025

34. Aasen, A. J., Liaaen-Jensen, S. 1967. Acta Chem. Scand. 2 1 : 970

35. Andrewes, A. G., Liaaen-Jensen, S. 1 972. Acta Chem. Scand. 26: In press

36. Arcamone, F., Camerino, B., Cotta, E., Franceschi, G., Penco, S. 1970. Gazz. Chim. Ital. 100 : 5 8 1

3 7 . Arpin, N., Fiasson, J. L., Bouchez-Dangye-Caye, M. P., Francis, G. W., Liaaen-Jensen, S. 1 97 1 . Phytochemistry 10: 1595

38. Yokoyama, H., White, M. J. 1 965. . J. Org. Chem. 30: 3994 39. Hertzberg, S., Liaaen-Jensen, S.,

Enzell, c., Francis, G. W. 1 969. Acta Chern. Scand. 2 3 : 3290

40. Liaaen-Jensen, S. 1 963. Bacterial Photosynthesis, 19 ed. H. Gest, A., San Pietro, L. P. Vernon. Yellow Springs, Ohio: Antioch Press.

4 1 . Pfennig, N. 1 967. Ann. Rev. Microbiol. 21 :285

42. Schmidt, K., Schiburr, R. 1970. Arch. Mikrobiol. 74: 3 50

43. Schmidt, K., Pfennig, N., LiaaenJensen, S. 1965. A rch. Mikrobioi. 52 : 132

44. Liaaen-Jensen, S., Hegge, E., Jackman, L. M. 1964. Acta Chem. Scand. 1 8 : 1703

45. Malhotra, H. C., Britton, G., Goodwin, T. W. 1970. Chem. Commun. 127

46. Weeks, O. B. 1971. Aspects of Terpenoid Chemistry and Biochemistry, Chap. 10, ed. T. W. Goodwin. London: Academic

47. Hertzberg, S., Liaaen-Jensen, S. 1967. Acta Chem. Scand. 21 : 15

48. Norgard, S., Francis, G. W., Jensen, A., Liaaen-Jensen, S. 1970. Acta Chem. Scand. 24: 1460

49. Weeks, O. B., Andrewes, A. G. 1970. Arch. Biochem. Biophys. 137:284

SO. Stransky, H., Hager, A. 1970. Arch. Mikrobiol. 7 1 : 164

51. Hertzberg, S., Liaaen-Jensen, S., Siegelman, H. W. 197 1. Phytochemistry 1 0 : 3 121

52. Aasen, A. J. , Liaaen-Jensen, S. 1966. Norw. I. Chem., Mining, Met. 26:128

53. Haxo, F. T. 1955. Fortschr. Chem. Org. Naturst. 12: 1 69

54. Aasen, A. J., Liaaen-Jensen, S. 1965. Acta Chem. Scand. 1 9 : 1843

55. Liaaen-Jensen, S., Weedon, B. C. L. 1964. Naturwissenschaften 5 1 :482

56. Arpin, N., Liaaen-Jensen, S. 1 967. Phytochemistry, 6:995

57. Andrewes, A. G. et al 1972. Acta Chem. Scand. 26: In press

58. Goodwin, T. W. 197 1 . Aspects of Terpenoid Chemistry and Biochemistry, Chap. 11. London: Academic

59. Egger, K., Dabbagh, A. G., Nitsche, H. 1969. Tetrahedron Lett. 2995

60. Charlton, J. M., Treharne, K. S., Goodwin, T. W. 1967. Biochem. I. 105:205

6 1 . Graebe, J. E. 1 968. Phytochemistry 7 :2003

62. Mercer, E. I., Davies, B. H., Goodwin, T. W. 1963 . Biochem. 1. 87: 317

63. Porter, J. W., Anderson, D. G. 1967. Ann. Rev. Plant Physiol. 1 8 : 1 97

64. Scharf, S. S., Simpson, K. L. 1968. Biochem. J. 106:311

65. Britton, G. 1971. Aspects of Ter-

penoid Chemistry and Biochemistry, Chap. 9, ed. T. W. Goodwin. London : Academic

66. Lee, T. C., Chichester, C. O. 1969. Phytochemistry 8 : 603

67. Shaw, D. V., Feldbruegge, D. H., Houser, A. R., Porter, J. W. 1968. Arch. Biochem. Biophys. 127 : 1 24

68. Varma, T. N. R., Chichester, C. O. 1962. A rch. Biochem. Biophys. 96:265

69. Jungalwala, F. B., Porter, J. W. 1967. A rch. Biochem. Biophys. 1 19 : 209

70. Anderson, D. G., Porter, J. W. 1962. Arch. Biochem. Biophys. 97 : 509

7 1 . Beeler, D. A., Porter, J. W. 1963. Arch. Biochem. Biophys. 100 : 1 67

72. Suzue, G. 1964. Bull. Chem. Soc. lap. 3 7 : 6 1 3

73. Goodwin, T . W . 197 1 . Biochem. I. 123 :293

74. Tefft, R. E., Goodwin, T. W., Simpson, K. L. 1970. Biochem. I. 1 17 : 921

75. Suzue, G. 1960. Biochim. Biophys. Acta 45 : 61 6

76. Beeler, D . A., Porter, J . W . 1962. Biochem. Biophys. Res. Commun. 8 : 367

77. Kushwaha, S. C., Suzue, G., Subbarayan, C., Porter, J. W. 1970. J. Bioi. Chem. 245 :4708

78. Subbarayan, C., Kushwaha, S. C., Suzue, G., Porter, J . W. 1970. Arch. Biochem. Biophys. 1 3 7 : 547

79. Jungalwala, F. B., Porter, J. W. 1965. Arch. Biochem. Biophys. 1 10 : 291

80. Rabourn, W. J., Quackenbush, F. W. 1956. Arch. Biochem. Biophys. 61: 111

8 1 . Decker, K., Uehleke, H. 1961. Z. Physiol. Chem. 323 : 6 1

82. Hill, H. M., Calderwood, S . K., Rogers, L. J. 1971. Phytochemistry 10:2051

83. Wells, L. W., ScheIble, W. J., Porter, J. W. 1964. Fed. Proc. 23 : 426

84. Hill, H. M., Rogers, L. J. 1969. Biochem. I. 113 : 31

85. Howes, C. D., Batra, P. P. 1970. Biochim. Biophys. Acta 222 : 174

86. Knypl, J. S. 1969. Naturwissenschaften 56 : 572

87. Coggins, C. W. Jr., Henning, G. L.,

MICROBIAL CAROTENOIDS 247 Yokoyama, H. 1970. Science 168: 1589

88. Davies, B. H. 1961. Biochem. J. 80:48 P

89. Simpson, K. L., Nakayama, T. O. M., Chichester, C. O. 1 964. J. Bacteriol. 88: 1688

90. Davies, B. H., Villoutreix, J., Williams, R. J. H., Goodwin, T. W. 1963. Biochem. J. 89 :96 P

91 . Raymundo, L. C., Griffiths, A. E., Simpson, K. L. 1967. Phytochemistry 6 : 1527

92. Williams, R. J. H., Britton, G., Goodwin, T. W. 1967. Biochem. J. 105 : 99

93. Claes, H. 1959. Z. Naturforsch. B 14:4

93b. Shneour, E. A. 1962. Biochim. Biophys. Acta 62: 534

94. Yamamoto, H. Y., Nakayama, T. O. M., Chichester, C. O. 1962. Arch. Biochem. Biophys. 97: 1 68

95. Yamamoto, H. Y., Chichester, C. 0., Nakayama, T. O. M. 1962. Photochem. Photobiol. 1 : 53

96. Yamamoto, H. Y., Chichester, C. O. 1965. Biochim. Biophys. Acta 109 : 303

97. Goodwin, T. W., Britton, G., Walton, J. J. 1968. Plant Physiol. 43 : suppl. 46

98. Hager, A. 1969. Planta 89:224 99. Donohue, H. V., Nakayama, T. O.

M., Chichester, C. O. 1 971. The Biochemistry of Chloropla�ts, 2 :43 1 ed. T. W. Goodwin. London : Academic

100. Davies, B. H. 1969. Pure Appl. Chem. 20 : 545

101. Liaaen-Jensen, S., Cohen-Bazire, G., Stanier, R. Y. 1961. Nature London 192: 1 168

102. Eimhjellen, K. E., Liaaen-Jensen, S. 1964. Biochim. Biophys. Acta 82:21

103. Liaaen-Jensen, S. 1967. Acta Chem. Scand. 2 1 :961

104. Francis, G . W . , Liaaen-Jensen, S. 1970. Acta Chem. Scand. 24: 2705

105. Weeks, O. B., Andrewes, A. G., Brown, B. 0., Weedon, B. C. L. 1969. Nature London 224: 879

106. Norgard, S., Aasen, A. J., LiaaenJensen, S. 1 970. Acta Chern. Scand. 24 : 2183

107. Aasen, A. J., Francis, G. W., Liaaen-Jensen, S. 1 969. Acta Chem. Scand. 23:2605

108. Zalokar, M. 1955. A rch. Biochem. Biophys. 5 6 : 3 1 8

109. Rilling. H . C . 1964. Biochim. Biophys. Acta 79 :464

1 10. Batra, P. P., Rilling, H. C. 1964. A rch. Biochem. Biophys. 107: 485

1 1 1 . Rau, W. 1969. Planta 84 :30 1 12. Rau, W., Lindemann, I. , Rau

Hund, A. 1961. Planta 56: 302 1 13 . Rilling, H. 1962. Biochirn. Bio

phys. Acta 65: 156 1 14. Barnett, H. L . , Lilly, V . G.,

Krause, R. F. 1956. Science 123 : 141

1 15. Ciegler, A. 1965. Advan. Appl. Microbial. 7 : 1

1 16. Heisenberg, M., Cerda-Olmedo, E. 1968. Mol. Gen. Genet, 102 : 1 87

1 17. Austin, D. J., Bu'Lock, J. D., Winstanley, D. J. 1 969. Biochem. J. 1 13 : 34 P

1 18. Sebek, 0., Jager, H. 1964. Abstr. 148th Meet. Am. Chem. Soc. 9 : 0

1 19. Austin, D. J., Bu'Lock, J . D., Drake, D. 1970. Experientia 26: 348

120. Barksdale, A. W. 1969. Science 166 :831

121. Thomas, D. M., Harris, R. C., Kirk, J. T. 0., Goodwin, T. W. 1967. Phytochemistry 6 : 3 6 1

122. Bu'Lock, J . D., Austin, D . J. 1970. Chem. Commun. 255

123. Eugster, C. H., Buchecker, R., Tscharner, C., Uhde, G., Ohloff, G. 1969. Helv. Chim. Acta 52 : 1 729

124. Krinsky, N. I. 1971. Carotenoids, Chap. IX, ed. O. Isler. Basel: Birkhiiuser

125. Batra, P. P. 1971. Photophysiology, Vol. 6, ed. A. C. Giese. New York : Academic

126. Wilson, T., Hastings, J. W. Photophysiology, 5 : 49, ed. A. C. Giese. New York: Academic

127. Fork, D. C., Amesz, J. 1969. Ann. Rev. Plant Physiol. 20: 305

128. Bergman, K. et al 1969. Bacteriol. Rev. 33 : 99

129. Griffiths, M., Sistrom, W. R., Cohen-Bazire, G., Stanier, R. Y. 1 955. Nature London 176: 1 2 1 1

130. Franck, J . 1 949. Photosynthesis in Plants, 293, ed. J. Franck, W. E. Loomis. Ames, Iowa: Iowa St. ColI. Press

1 3 1 . Sistrom, W. R., Griffiths, M., Stanier, R. Y. 1956. 1. Cell. Compo Physiol. 48 :473

248 LlAAEN-JENSEN & AN DREWES

1 32. Stanier, R. Y. 1960. Harvey Lect. 54 : 2 19

133. Fujimori, E., Livingston, R. 1957. Nature London 1 80 : 1036

1 34. Schenck, G. O. 1 954. Naturwissenschaften 41 :452

135. Foote, C. S., Wexler, S. 1964. I. Am. Chem. Soc. 86: 3879

1 36. Corey, E. J., Taylor, W. C. 1 964. I. Am. Chem. Soc. 86:3681

137. Foote, C. S., Wexler, S. 1964. I. Am. Chem. Soc. 86:3880

1 3 8. Foote, C. S., Denny, R. W. 1964. I. Am. Chem. Soc. 90: 623

1 39. Chessin, M., Livingston, R., Truscott, T. G. 1966. Trans. Faraday Soc. 62 : 1 5 1 9

140. Foote, C. S., Chang, Y. C., Denny, R. W. 1970. I. Am. Chern. Soc. 92 :5216

14 1 . Claes, H. 1960. Biochem. Biophys. Res. Commun. 3 : 585

142. Claes, H., Nakayama, T. O. M. 1959. Nature London 1 8 3 : 1053

143. Foote, C. S., Denny, R. W., Weaver, L., Chang, Y., Peters, J. 1 970. Ann. NY Acad. Sci. 1 7 1 : 1 3 9

143b. Foote, C., 1969. Int. Carotenoid Symp., 2nd, Las Cruces, New Mexico

144. Foote, C. S., Brenner, M. 1 968. Trans. Faraday Soc. 57: 6041

145. Mousseron-Canet, M., DaIle, Jr. P., Mani, J. C. 1968. Tetrachedron Lett. 57 : 603

146. Foote, C. S. 1 968. Accoun ts Chem. Res. 1 : 104

147. Mathis, P. 1 962. Progress in Photosynthesis Research, 2 : 8 18, ed. H. Metzner. Tlibingen: lnst. Chern. Pfianzephysiol.

148. Mathis, P., Galmiche, J. M. 1967. C. R. Acad. Sci., Ser. D 264: 1903

149. Mathis, P. 1 966. C. R. Acad. Sci., Ser. D 263 : 1770

150. Wolff, C., Witt, H. T. 1 969. Z. N aturforsch. B24: 103 1

1 5 1 . Witt, K, Wolff, C. 1970. Z. Naturforsch. B25 :387

1 52. Smith, L., Ramirez, J. 1960. I. BioI. Chem. 235 :2 1 9

1 53. Fleishman, D . E., Clayton, R. K. 1968. Photochem. Photobiol. 8 : 287

1 54. BaltschetIsky, M. 1 969. Arch. Biochem. Biophys. 1 30: 646

155. Jackson, J. B., Crofts, A. R. 1 969. Febs lett. 4: 1 8 5

156. Neumann, J . , Ke, B . , Dilley, R. A. 1 970. Plant Physiol. 46 : 86

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