Physodes and the Phenolic Compounds of Brown Algae. Composition and Significance of Physodes in vivo

Ragan, Mark A.

doi:10.1515/botm.1976.19.3.145

Cited by 74 publications

(29 citation statements)

References 48 publications

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“…For example, proteins (i.e., tyrosine moieties; Tsuge and Matsubara, 1985), seed coats of higher plants (Van Bergen et al, 1993, and modified lignin (Saiz-Jimenez and De Leeuw, 1986;Collinson et al, 1994;Hatcher and Spiker, 1988). The occurrence of polyphenolic compounds in marine macroalgae has also been described (Ragan, 1976;Ragan and Craigie, 1978;Van Alstyne, 1988;J.D.H. van Heemst et al, unpubl.…”

Section: Sources Of the Pyrolysis Productsmentioning

confidence: 78%

Changes in kerogen composition across an oxidation front in Madeira Abyssal Plain turbidites as revealed by pyrolysis GC-MS

Damsté¹,

Hoefs²,

Leeuw³

et al. 1998

Proceedings of the Ocean Drilling Program, 157 Scientific Results

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Isolated kerogens from Madeira Abyssal Plain turbidite samples were qualitatively and semiquantitatively studied by means of analytical pyrolysis for the effect of oxygen exposure on organic matter preservation. The initial organic matter in the turbidite is very homogeneous and relatively high and offers an ideal case for the study of oxygen effects on organic matter preservation without the usual complications of varying sources or sedimentation rates and bioturbation. From all four studied turbidites, one sample from the oxidized part of the turbidite was compared with two samples from the unoxidized part. The aliphatic character of the kerogens after postdepositional oxidation has increased significantly, as revealed by the abundance of the n-alkanes and n-alk-1-enes in the oxidized turbidite. At the same time, the contribution of the isoprenoid alkanes and alkenes and the alkylthiophenes to the pyrolysate has decreased significantly. The relative abundances of alkylbenzenes, alkylnaphthalenes, alkylphenols, alkylindenes, and alkan-2-ones in the pyrolysates have remained relatively constant upon oxidation. The alkylbenzene, alkylphenol, alkylnaphthalene, n-alkane, and n-alk-1-ene, isoprenoid alkane, and alkene internal distributions are substantially altered in the oxidized samples. This study shows that postdepositional oxidation of sedimentary organic matter by oxygen is far more severe than by sulfate alone. Furthermore, it is clear that oxidation of the organic matter is, to a significant degree, selective.

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Section: Sources Of the Pyrolysis Productsmentioning

confidence: 78%

Changes in kerogen composition across an oxidation front in Madeira Abyssal Plain turbidites as revealed by pyrolysis GC-MS

Damsté¹,

Hoefs²,

Leeuw³

et al. 1998

Proceedings of the Ocean Drilling Program, 157 Scientific Results

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“…Although phenolic compounds are thought to have some antifouling properties (Sieburth & Conover 1965), phenolics in brown algae are contained in sealed vesicles called physodes (Ragan 1976). In the epiphytic association studied here, potential toxic effects of contacting polyphenolic compounds may be minimized by the thick, heavy calcification of Lichenopora novae-zelandiae colonies, a s well a s by biological membranes surrounding physodes.…”

Section: Discussionmentioning

confidence: 99%

Epiphytism on Agarum fimbriatum: can herbivore preferences explain distribution of epiphytic bryozoans?

Durante¹,

Chia²

1991

Mar. Ecol. Prog. Ser.

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ABSTRACT-The association between an epiphytic stenolaemate bryozoan, Lichenopora novaezelandiae, its algal host substratum Agarum fimbriatum (Order Laminariales). and an herbivorous snail, Tegirla pulligo (Subclass Prosobranchia), was investigated. Field surveys showed that bryozoan age distributions were spatially correlated with algal age distributions: younger bryozoans were concentrated on the youngest parts of the algae, and vice versa. In laboratory experiments, planktonic larvae of this bryozoan displayed a strong preference for A. fimbriatum over other kelps, and preferred settling on younger regions of A. fimbriatum over older regions. Although 7: pulligo was deterred from feeding on A. fimbriatum as compared to other kelps, the snails nonetheless displayed within-thallus discrimination for tissues of different ages of this low-priority food item. Younger tissues, with or without resident epiphytic bryozoans, were consumed in much lower quantities than older tissues. Adult bryozoans on older A. fimbriatum deterred feeding by the gastropods, revealing an indirect beneficial effect of epiphytic organisms on their host algal substrata. Previous dlet of 7: pulligo maintained in the laboratory failed to influence significantly the snails's consumption of A. fimbriatum.

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“…They occur in cells in vesicles known as physodes and are also deposited in cell walls Clayton, 1998a, 1999). Their functional significance has been the subject of some debate for well over a century (see Ragan, 1976;Ragan and Glombitza, 1986;Schoenwaelder, 2002a). However, it is only in the past few years that the probability that phlorotannins have multiple roles has been acknowledged Targett, 2002, 2003).…”

Section: A U T H O R ' S P E R S O N a L C O P Ymentioning

confidence: 99%

Screening capacity of UV-absorbing compounds in spores of Arctic Laminariales

Roleda

Clayton

Wiencke

2006

Journal of Experimental Marine Biology and Ecology

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The functional significance of phlorotannins as ultraviolet radiation screens in brown algae is presented. Spectral analysis of zoospore suspensions of the three Arctic Laminariales Saccorhiza dermatodea, Alaria esculenta and Laminaria digitata showed strong absorption in the UV waveband, characteristic of phlorotannins. An induction in the synthesis of the UV-absorbing compound in zoospore suspensions of S. dermatodea and A. esculenta was observed as an increase in absorbance in the UV region after 8 h exposure to the whole light spectrum. Transmission of UVR was also negatively correlated with zoospore density in both these species but not in L. digitata. 'Biofilters' constructed from UV-transparent acrylic sheet, containing zoospore suspensions or solutions of phloroglucinol showed varying capacity to protect zoospore cultures from the lethal effects of ultraviolet radiation. Phloroglucinol protects the zoospores from damage by screening out the much harmful shorter UV-B spectra (280-290 nm). Cultured spores of A. esculenta and L. digitata after exposure to the whole light spectrum covered by filters containing phloroglucinol showed high rates of germination, unlike controls covered by seawater-only filters that showed 100% mortality. Biofilters containing zoospore suspensions act as buffers and showed variable UV-protection properties on the germination of its conspecies. At highest zoospore density (∼4 ×10 6 spores ml − 1 ), zoospores were observed to screen UV radiation maintaining viability among shielded spores in all species investigated. The protective function of zoospore film is, however, density-dependent in L. digitata. At lower spore density, UV-screening function in S. dermatodea and A. esculenta is attributed to their capacity to accumulate and release UV-absorbing compounds into the medium. Ultraviolet radiation transmission by zoospore suspensions of Saccorhiza and Alaria decreased during exposure to the whole light spectrum which is consistent with the earlier observation of enlarged phenolic vesicles following UVR exposure. The increase in vesicle size and the corresponding increase in UV-absorbing capacity may contribute to greater tolerance of UVR exposure in both species.

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Physodes and the Phenolic Compounds of Brown Algae. Composition and Significance of Physodes in vivo

Cited by 74 publications

References 48 publications

Changes in kerogen composition across an oxidation front in Madeira Abyssal Plain turbidites as revealed by pyrolysis GC-MS

Changes in kerogen composition across an oxidation front in Madeira Abyssal Plain turbidites as revealed by pyrolysis GC-MS

Epiphytism on Agarum fimbriatum: can herbivore preferences explain distribution of epiphytic bryozoans?

Screening capacity of UV-absorbing compounds in spores of Arctic Laminariales

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