Fumarprotocetraric Acid Research Articles

Quantitative determination of protolichesterinic- and fumarprotocetraric acids in Cetraria islandica by high-performance liquid chromatography

A quantitative reversed-phase HPLC method for the analysis of protolichesterinic- and fumarprotocetraric acids in Cetraria islandica (L.) Ach. is described. The compounds were extracted from dry plant material with acetone. HPLC analysis was performed using a LiChrosorb RP-8 column, isocratic elution and UV detection. The method was applied to the quantification of protolichesterinic- and fumarprotocetraric acids in plant material collected in various locations within Iceland. Results showed protolichesterinic acid content of Cetraria islandica to vary between 0.1–0.5% dry weight and fumarprotocetraric acid content to vary between 2.6–11.5% depending on collection site.

Growth retarding activity of lichen substances against the polyphagous herbivorous insect Spodoptera littoralis

Fourteen frequently occurring lichen substances including two depsides, seven depsidones and four pulvinic acid derivatives as well as an anthraquinone, were studied for their influence on growth and development of polyphagus herbivore Spodoptera littoralis. Whereas larval survival was usually not affected most of the compounds studied caused a pronounced reduction of larval growth in chronic feeding experiments with neonate larvae. The ED 50s of the most active compounds oxyphysodic acid and vulpinic acid were 11.2 and 17.2 μmol g −1 dry wt., respectively whereas the natural concentrations of both compounds were 41 μmol g −1 dry wt. for the former (in Hypogymnia physodes) and 137 μmol g −1 dry wt. (in Letharia vulpina) for the latter. Several of the lichen compounds including oxyphysodic acid, fumarprotocetraric acid or calycin when fed to neonate larvae during the first 6 days of their development caused a pronounced increase of the larval period and/or a high incidence of developmental malformations in the resulting imagines, indicating deleterious long term effects of the respective compounds. The growth-retarding effects of oxyphysodic acid or norstictic acid towards larvae of S. littoralis were not restricted to the pure compounds but were also observed when crude lichen extracts were incorporated into artificial diet. However, lichens containing the depside atranorin or the anthraquinone parietin were usually more active than the pure compounds indicating the presence of so far unknown bioactive compounds in the respective extracts.

Carotenoids in Representatives of the Lichen Genus Cladonia in North America

The study of carotenoids in 20 taxa of Cladonia from North America revealed antheraxanthin, astaxanthin, canthaxanthin, capsochrome, f3-apo-2'carotenal, a-carotene, 3-carotene, 3-cryptoxanthin, a-doradexanthin, 3'-epilutein, flavoxanthin, lutein, lutein epoxide, mutatoxanthin, violaxanthin, and zeaxanthin. The total carotenoid content of the material ranged from 10.93 gg g-' in C. ecmocyna to 52.31 gg g-' in C. cervicornis. Representatives of the lichen genus Cladonia are widespread in a variety of environments throughout the world. The purportedly wide distribution of many species results in their exposure to markedly differing habitats and may exercise a profound effect on their morphological and chemical characteristics. Variation within Cladonia species and the detection of new species based on consistent, genetically derived character states have been the focus of intensive activity. The interpretation of such variations and their appropriate taxonomic treatment depends upon the discovery and elucidation of reliable characters, including secondary chemistry. Recent chemotaxonomic work in Cladonia and other genera has focused on the unique secondary phenolic compounds and fatty acids produced by lichens (Huovinen et al. 1989a,b, 1990). The analysis of carotenoids in representatives of the Cladoniaceae from northeastern Poland (Czeczuga 1985), Germany (Czeczuga & Doll 1991), and other northern hemisphere localities (Czeczuga et al. 1991) demonstrated that a number of carotenoids are characteristic and perhaps diagnostic in Cladonia. The present study is a continuation of investigations utilizing carotenoids as taxonomic indicators in Cladonia. In this study, we compare the carotenoid contents of various taxa from North America, with a focus on Cladoniae of the western United States, and California in particular. Although the carotenoid contents of Cladonia species from Europe have been intensively studied, this is the first assay of thalli exclusively from North America. The present study was initiated in order to provide preliminary observations on several questions. In this study, we endeavored to establish whether significant differences occur between the carotenoids of North American taxa and those of their Old World counterparts. Of primary interest was the question of carotenoid distribution patterns as a corollary to taxonomic groupings. We attempted to detect patterns between morphologically and phenolically similar species at various taxonomic levels regarding their carotenoid contents. For example, specimens 2, 3, 4, and 20 (Table 2) are morphologically similar on the basis of central proliferations from their podetia, and share a fumarprotocetraric acid-based phenolic chemistry. They share an informal status as members of a C. cervicornis moiety within Cladonia section Cladonia (Ahti 1978). We also assayed species (Table 2, specimens 1, 17, 18) that are taxonomically recognized within Cladonia section Perviae. Two of these were recently described from western North America (Hammer 1989a, 1992) and may be closely related; thus, similarities or differences in their carotenoid contents would be of great interest. Patterns in carotenoid distribution were also sought amongst phenolically similar but morphologically dissimilar taxa; specimens 4, 5, 6, 8, 9, 13, 14, 15, and 16 (Table 2) are apparently morphologically unrelated although they all contain fumarprotocetraric acid and belong to section Cladonia (Huovinen et al. 1990). Finally, we chose specimens from several subgeneric groups to compare the carotenoid contents of various sections in Cladonia. In many cases specimens from critical localities were studied. These were chosen in part for their historical or biogeographical importance. For example, specimen 10 (Table 2) was collected at or near C. A. Robbins' locus of activity in Wareham, Massachusetts (Robbins 1924). Robbins' collecting work and his taxonomic efforts in Cladonia were influential in subsequent decades (Thomson 1967), ' Present address: College of General Studies, Boston University, 871 Commonwealth Avenue, Boston, MA 02215. 0007-2745/94/67-70$0.55/0 This content downloaded from 207.46.13.101 on Sat, 08 Oct 2016 06:00:32 UTC All use subject to http://about.jstor.org/terms 68 THE BRYOLOGIST [VOL. 97 TABLE 1. Carotenoids from 20 taxa of Cladonia. Carotenoid structures are shown in Figure 1. Carotenoid Structure Semisystematic name 1. Antheraxanthin D-R-E 5,6-epoxy-5,6-dihydro-f,f-carotene-3,3'-diol 2. Astaxanthin G-R-G 3,3'-dihydroxy-/3,-carotene-4,4'-dione 3. Canthaxanthin F-R-F f,f-carotene-4,4'-dione 4. Capsochrome H-RI-I 5,8-epoxy-3,3'-dihydroxy-5,8-dihydro-f3,x-carotene-6'-one 5. f3-apo-2'-Carotenal B-R-J 3',4'-didehydro-2'-apo-fl-carotene-2'-al 6. a-Carotene A-R-B f#m-carotene 7. #-Carotene B-R-B #,#-carotene 8. /-Cryptoxanthin B-R-D #,#-carotene-3-ol 9. a-Doradexanthin C-R-G 3,3'-dihydroxy-3,e-carotene-4-one 10. 3'-Epilutein C-R-D 3,E-carotene-3,3'-diol (stereoisomeric) 11. Flavoxanthin C-RI-H 5,8-epoxy-5,8-dihydro--,e-carotene-3,3-diol 12. Lutein C-R-D f,e-carotene-3,3'-diol 13. Lutein epoxide C-R-E 5,6-epoxy-5,6-dihydro--,e-carotene-3,3'-diol 14. Mutatoxanthin D-R2-H 5,8-epoxy-5,8-dihydro-f,f-carotene-3,3'-diol 15. Violaxanthin E-R-E 5,6,5',6'-diepoxy-5,6,5',6'-tetrahydro-j3,3-carotene-3,3'-diol 16. Zeaxanthin D-R-D (,f-carotene-3,3'-diol but his collecting sites were not revisited until quite recently (Hammer, unpubl.). Other collecting sites included in this paper reflect questions regarding numerous Cladonia species that appear to be limited in their distribution and perhaps endemic to western North America (Hammer 1989a,b, 1991; Hammer & Ahti 1990). Their circumscribed range suggests that these species may possess specific environmental requirements. The geographical isolation of some populations has led to a modified sibling-species hypothesis, which presumes the presence of unique secondary phenolics among certain members of geographically isolated populations (Hammer 1989b). Likewise, the presence of

Cladonia Azorica in the British Isles

Cladonia azorica is widespread in western Great Britain, mainly as the grey colour-form lacking usnic acid. Cladonia azorica is distinguished from the related species C. portentosa and C. mediterranea by the presence of fumarprotocetraric acid, and from C. ciliata by a number of characters including the presence of perlatolic acid. The structure of the pycnidial wall may have some taxonomic significance in Cladonia subgenus Cladin

Cladonia azorica in the British Isles

Abstract: Cladonia azorica is widespread in western Great Britain, mainly as the grey colour-form lacking usnic acid. Cladonia azorica is distinguished from the related species C. portentosa and C. mediterranea by the presence of fumarprotocetraric acid, and from C. ciliata by a number of characters including the presence of perlatolic acid. The structure of the pycnidial wall may have some taxonomic significance in Cladonia subgenus Cladina.

An investigation of the allergenic constituents of Cladonia stellaris (Opiz) Pous & Vezda ('silver moss', 'reindeer moss' or 'reindeer lichen').

The sensitizing potency of Cladonia stellaris ('reindeer lichen', 'silver moss') extracts was determined in guinea pigs by a modified FCA (Freund's complete adjuvant) test. The lichen showed a moderate sensitizing potency. Similar investigations with pure common lichen constituents revealed a moderate sensitizing potency for fumarprotocetraric acid and atranorin and a weak one for evernic acid, stictic acid and both forms of usnic acid. Although generally weak, (-)-usnic acid was at least 2 x stronger than (+)-usnic acid. After separation of the Cladonia ether extract into 'usnic-acid-free' and 'usnic-acid-containing' fractions, perlatolic acid was identified as the main allergenic constituent of the 'usnic-acid-free' fraction. Stictic, evernic, fumarprotocetraric acid and atranorin were not detectable. Lichens and lichen products generally possess a weak to moderate sensitizing capacity. Compared with common sensitizers of occupational and environmental importance, these products play only a minor rôle.

Variation in the Cladonia chlorophaea Complex. I: Morphological and Chemical Variation in Southern Appalachian Populations

Variation in the Cladonia chlorophaea Complex. I: Morphological and Chemical Variation in Southern Appalachian Populations

Pertusaria aspergilla, the correct name for P. dealbata auct. (lichenized Ascomycotina: Pertusariales)

SummaryLaundon, J. R.: Pertusaria aspergilla, the correct name for P. dealbata auct. (lichenized Ascomycotina: Pertusariales). ‐ Taxon 41: 744‐745. 1992. ‐ ISSN 0040‐0262.Pertusaria aspergilla (Achar.) Laundon, comb. nov., replaces P. dealbata auct., non (Achar.) Crombie, and P. dealbescens auct., non Erichsen, a superfluous name.

Cladonia petrophila, a New Species from Eastern North America

Cladonia petrophila, an overlooked, usually sterile species, morphologically similar toC. apodocarpa andC. caespiticia, is described as new on the basis of its distinctive chemistry, perlatolic and fumarprotocetraric acids, and habitat preference for moist non-calcareous rock.

Parmelia masonii, a New Lichen Species (Ascomycota) from the Himalayas

The new species Parmelia masonii, an apparent Himalayan endemic, is distinguished from other members of the genus by the distinctive brown color, lack ofatranorin in the upper cortex, and presence of fatty acids or fumarprotocetraric acid, or both, in the medulla. The lichen genus Parmelia is now known to contain a total of 39 species. In his recent monograph of the genus Parmelia (s.s.), Hale (1987) included 38 species. Asia is ap- parently the major center of diversity for the genus, with a total of 17 species including 10 endemics. Hale reported eight species as occurring in the Hi- malayas, although none of them is endemic to that region. It is therefore interesting to report the ex- istence of a previously undescribed species, appar- ently endemic to the Himalayan region and at pres- ent known only from Nepal. This species is named in honor of the late Dr. Mason E. Hale, Jr., the preeminent student of the Parmeliaceae.

Cliostomum(Lichen-Forming Ascomycotina) in North America and Europe

C. luteolum and C. vitellinum are newly described species, rare on trees with acidic bark in oceanic northeastern United States and southeastern Canada. C. luteolum is closely related to C. cirrugatum but has yellow rather than orange apothecia and an effuse, sorediate thallus. C. vitellinum has distinctive, tiny, bright yellow apothecia on a thin, sorediate thallus; it contains fumarprotocetraric acid. Apothecia are biatorine and spores are bacilliform and 1- to 3-septate. C. griffithii occurs on the east and west coasts of North America and in Europe, and C. corrugatum occurs in Europe (...)

Systematics of Some Reindeer Lichens (Cladonia Subg. Cladina) in the Southern Hemisphere

AbstractCladonia arbuscula subsp. squarrosa (Wallr.) Ruoss and C. stygia (Fr.) Ruoss are reported for the first time from the Southern Hemisphere. Populations of C. arbuscula in New Zealand and Australia are recognized as subsp. stictica Ruoss, subsp. nov., usually containing stictic acid, norstictic acid (first report in subg. Cladina), and sometimes also the fumarprotocetraric acid complex. C. laevigata (Vainio) Gyelnik is reinstated in Cladonia subg. Cladina sect. Tenues, while C. stygia is considered to belong to sect. Crustaceae rather than to sect. Tenues. C. confusa R. Sant. is morphologically highly variable, although chemically uniform, usually containing usnic acid and perlatolic acid. An usnic acid-deficient chemodeme is reported as new to New Zealand.

Contact sensitivity to oak moss.

Oak moss allergy was the principle allergen in contact sensitivity to perfumes (45%); 31 patients reacting to oak moss were studied. The sensitivity was attributed to contact with perfumes in 20, lichens in 7 and unknown in 4. Atranorin was the most frequent allergen, followed by usnic, evernic and fumarprotocetraric acids. Concomitant allergy occurred to several lichen acids and also to balsam of Peru, colophony and other fragrance components.

Pigment analysis of sun and shade populations of Cladonia verticillaris

The natural occurrence of the lichen Cladonia verticillaris as sunny and shaded populations implies changes in the pigment content. Shade specimens contain more chlorophyll a and b as well as more α- and β-carotene than those found in unshaded lichens. However, lichens growing in sunny locations contain more methyl β-orcinol carboxylate, orcinol and fumarprotocetraric acid than those found in lichens growing under low light intensities. No structural differences in the chloroplasts of the two species bave been detected.

Allelopathic effects of Cladonia cristatella on ectomycorrhizal fungi common to bituminous strip-mine spoils

Acetone–toluene extracts of Cladonia cristatella inhibited the growth of fungi known to form ectomycorrhizal associations with trees commonly found on bituminous strip-mine spoils in western Pennsylvania. Growth of Pisolithus tinctorius and Suillus luteus was completely inhibited by C. cristatella extracts over a 30-d bioassay period. Thelephora terrestris was dead after 17 d. The growth of Cenococcum graniforme was unaffected by lichen extracts. D-Usnic acid, a major secondary compound of the C. cristatella extract, was found to inhibit the growth of P. tinctorius. This inhibition, however, did not account for the total inhibition of P. tinctorius demonstrated by the gross acetone–toluene extract. Other secondary compounds, and potential allelopathic substances, present in the extract were barbatic acid, didymic acid, condidymic acid, subdidymic acid, fumarprotocetraric acid, squamatic acid, and rhodocladonic acid.

Depsidones and fatty acids of Parmelia stygia

One Russian sample of the lichen Parmelia stygia has yielded fumarprotocetraric acid, while a second contained the same compound accompanied by colensoinic, lobaric, caperatic and norcaperatic acids.

Cladonia chlorophaea sens. lat. in Southeastern Australia

The distribution of species within the Cladonia chlorophaea group in southeastern Australia has been determined from a chemical examination of 148 specimens. The commonest species is Cladonia merochlorophaea Asah.; Cladonia grayii Merr. ex Sandst. does not appear to occur in the area studied. Cladonia homosekikaica Nuno is reported for the first time from Australia. The Cladonia chlorophaea group contains several morphologically similar species which are differentiated on the basis of their constituent lichen acids. Five species of this group occur in Australia viz. C. chlorophaea (Flirke ex Sommerf.) Spreng. (fumarprotocetraric acid); C. cryptochlorophaea Asah. (cryptochlorophaeic acid ? fumarprotocetraric acid with traces of paludosic acid); C. merochlorophaea Asah. (merochlorophaeic and 4-O-methyl- cryptochlorophaeic acids ? fumarprotocetraric acid with traces of homosekikaic and cryp- tochlorophaeic acids); C. conoidea Ahti (atranorin and fumarprotocetraric acid) and C. homosekikaica Nuno, with homosekikaic and fumarprotocetraric acid. A recent chemical examination of 148 specimens of C. chlorophaea sens. lat. collected in southeastern Australia (excluding Tasmania) gave the results shown in Table 1. The specimens were collected from 31 locations as shown in Fig. 1. The altitudes of the collection sites ranged from 2200 m (Mt. Kosciusko, N.S.W.) to 50 m (Gladesville, N.S.W.). No collections were made from north and west of the 500 mm isohyet; C. chlorophaea was not found in this dryer area (Rogers & Lange 1972). Acetone extracts of the specimens were examined by thin-layer chromatography (Culberson 1972) and the separated com- pounds were detected with sulphuric acid (Culberson 1972) and MBTH (Archer 1978). Grayanic acid, for use as a reference compound, was extracted from Gymnoderma mela- carpum (Wilson) Yoshimura (Chester & Elix 1980). The results in Table 1 show that the most frequently collected species was C. merochloro- phaea; 58% of the specimens contained fumarprotocetraric acid compared to 89% in North America (Bowler 1972); C. merochlorophaea var. novochlorophaea Sipman (Sipman 1973) was not found. C. chlorophaea sens. str. formed 30% of the specimens examined and a further 13% were C. cryptochlorophaea; 75% of these contained fumarprotocetraric acid compared to 82% in North America. The less common species were C. conoidea and C. homosekikaica; the latter species is reported from Japan (Nuno 1975). The apparent absence of C. grayi from southeastern Australia is in marked contrast to the distribution of the species within the C. chlorophaea group reported from the Northern Hemisphere (Nourish & Oliver 1976), particularly from North Carolina (Kristinsson 1971) and the southern Appalachians (Dey 1978) where it was the most common species found. Cladonia merochlorophaea, the most common species in southeastern Australia, occurs relatively infrequently in North America. Cladonia grayi is not reported from South Aus- tralia (Filson & Rogers 1979) or Tasmania (Wetmore 1963) but is reported from South America (Dey 1978) and New Zealand (Martin 1958). However, a recent chemical ex-

The Cladonia chlorophaea-C. fimbriata Complex in Western Washington

Members of the Cladonia chlorophaea-C. fimbriata complex were collected in western Washington in the summer of 1979 to examine their secondary- product chemistry, morphology, and distribution. Eight chemotypes were identi- fied, including four that had not previously been reported from this region and one characterized by the production of4-O-methylcryptochlorophaeic acid as the major secondary product that is new. Specimens producing only fumarprotocetraric acid in this region could be separated into two groups on the basis of morphology. The first group was characterized by the production of granular soredia, short trumpet- shaped podetia, and compound apothecia, and was referred to C. chlorophaea sens. str. The second group had farinose soredia, goblet-shaped podetia with den- tate margins, and simple apothecia, and was referred to C. fimbriata (L.). These two species are the most abundant and widespread members of this complex in western Washington and were collected from all habitats from which collections were made. Most of the remaining chemotypes could also be divided into two groups according to chemistry, morphology, and distribution. Two chemotypes produced closely related fatty acids, rangiformic acid and protolichesterinic acid as their major secondary products and exhibited a close morphological affinity to C. fimbriata on the basis of their farinose soredia, podetial shape, and simple apothecia. In addition, these two chemotypes were collected more frequently from woody substrates and forested areas than the other members of this complex. Three of the chemotypes contained the closely related orcinol meta-depsides mer- ochlorophaeic acid, 4-O-methylcryptochlorophaeic acid and sekikaic acid as their major secondary products. These chemotypes had large trumpet-shaped podetia, granular to corticate soredia, and compound apothecia. Specimens of this group were collected predominately from open areas, especially the natural prairies that occur in southwestern Washington. In fact, the sekikaic acid chemotype is appar- ently restricted to these prairies in this part of its range. Excluded from these two groups are two remaining chemotypes that produce bourgeanic acid and atranorin, respectively.

A New Lecanoric Acid-Producing Usnea from Mexico

Usnea lecanorica (Ascomycotina, Usneaceae), a new species of the U. florida group from south-central Mexico, differs from all other known species of its genus by producing lecanoric acid as the major medullary constituent. The new Mexican lichen species Usnea lecanorica (Ascomycotina, Usneaceae), the subject of this report, is the first member of its genus known to produce lecanoric acid. Unlike the some 18 0-orcinol products characteristic of many scores of species in this genus, lecanoric acid is a para-depside of the orcinol series, a category previously known to be represented in Usnea by only evernic acid in U. longissima ssp. jesoensis Asah. and U. trichodea Ach. Evernic acid is the 4-O-methyl derivative of lecanoric acid; it probably also occurs in trace amounts in the new species described here. The natural but variable genus Usnea (discussion: Krog 1976) consists of about 500 species. Although thoroughly cosmopolitan, it achieves greatest species diversity in warmtemperate, subtropical and upland-tropical vegetations. The fruticose thallus with its central cord is so distinctive that the chemical data now recorded from approximately 200 species are surely correctly assigned at the generic level. Taxonomy at the species level, however, is confused because in many groups the major evolutionary modifications have been in secondary-product chemistry and amplitude of ecologic tolerance. Usnea lecanorica belongs to the U. florida complex--characteristically tufted lichens with conspicuous apotheciaconstituting in North America a series of 13 chemotypes as determined from a thin-layer chromatographic survey of 358 specimens (Fiscus 1972). No micromorphological analyses have been made, and consequently it is unknown if any of the small morphological variations seen in the U. florida complex consistently accompany major chemical discontinuities. The U. florida group in North America is characterized by certain 0-orcinol depsides (diffractaic, squamatic and thamnolic acids) and depsidones (connorstictic, constictic, 2'O-methylpsoromic (= conpsoromic), fumarprotocetraric, galbinic, norstictic, protocetraric, psoromic, salazinic and stictic acids). Additionally, some members of the U. florida group make fatty acids (including caperatic and bourgeanic acids); they all make the yellow pigment usnic acid and some produce other pigments as well. It was consequently a surprise to find two C+ red Mexican collections that produced the unsuspected orcinol depside lecanoric acid. The two small original collections were made by Robert W. Cruden in 1966 at a mountain locality some 25 km southwest of Toluca in the state of Mexico. We found four more specimens at the same locality ten years later during one of several general collecting trips for lichens of the mountain forests of south-central Mexico. Curiously, these four were the only examples of this chemotype among the many specimens of the U. florida group taken throughout the extensive regions visited. The cool, relatively moist locality near Toluca is above 3000 m elevation and is forested with Abies religiosa and Pinus sp. The new species grows upon both these trees. The most common congeneric companion 007-2745/83/254-256$0.45/0 This content downloaded from 207.46.13.163 on Fri, 08 Jul 2016 06:11:51 UTC All use subject to http://about.jstor.org/terms 1983] CULBERSON ET AL.: A NEW USNEA 255

A NEW CHEMICAL STRAIN OF CLADONIA FURCATA (HUDS.) SCHRAD. (LICHENES)

Acta Botanica NeerlandicaVolume 31, Issue 5-6 p. 491-494 Brief Communication A NEW CHEMICAL STRAIN OF CLADONIA FURCATA (HUDS.) SCHRAD. (LICHENES) A. Barendregt, A. Barendregt Instituut voor Systematische Plantkunde, Heidelberglaan 2, 3584 CS UtrechtSearch for more papers by this authorP. J. L. Van Den Dries, P. J. L. Van Den Dries Instituut voor Systematische Plantkunde, Heidelberglaan 2, 3584 CS UtrechtSearch for more papers by this authorH. J. M. Sipman, H. J. M. Sipman Instituut voor Systematische Plantkunde, Heidelberglaan 2, 3584 CS UtrechtSearch for more papers by this author A. Barendregt, A. Barendregt Instituut voor Systematische Plantkunde, Heidelberglaan 2, 3584 CS UtrechtSearch for more papers by this authorP. J. L. Van Den Dries, P. J. L. Van Den Dries Instituut voor Systematische Plantkunde, Heidelberglaan 2, 3584 CS UtrechtSearch for more papers by this authorH. J. M. Sipman, H. J. M. Sipman Instituut voor Systematische Plantkunde, Heidelberglaan 2, 3584 CS UtrechtSearch for more papers by this author First published: November 1982 https://doi.org/10.1111/j.1438-8677.1982.tb01664.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume31, Issue5-6November 1982Pages 491-494 RelatedInformation