''Dictyota'' is a genus of brown

seaweed Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

in the family

Dictyotaceae Dictyotaceae is large family (biology), family of brown algae (class Phaeophyceae). Members of this family generally prefer warmer waters than other brown algae. ''Lobophora variegata'' (= ''Pocockiella varieagata'') often presents a beautiful b ...

. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals ( diterpenes) which have potential medicinal value. As at the end of 2017, some 237 different diterpenes had been identified from across the genus.

Taxonomy and Nomenclature

The genus ''Dictyota'' was first described by Jean Vincent Lamouroux in 1809. The name ''Dictyota'' is derived from the Greek word “Διχτυον” meaning “net” or “network”, referring to the inner cellular structure of specimens when viewed under a microscope, which features netted cortical and medullary cells. ''Dictyota'' belongs to the order Dictyotales and the SSDO-clade, which also includes the orders

Sphacelariales Sphacelariales is an order of brown algae Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae ...

, Syringodermatales, and Onslowiales. The family Dictyotaceae is divided into two tribes: Dictyoteae and Zonarieae. The former have a single lens-shaped apical cell from which the thallus grows, while the latter are characterized by a row or cluster of apical cells. The genera ''Glossophora'', ''Glossophorella'', and ''Pachdictyon'' are synonyms of ''Dictyota'' as DNA sequencing revealed that they were closely related.

Morphology

External characteristics

''Dictyota'' has "flat, ribbon-like axes" which exhibit dichotomous branching that may be either isotomous (equal or symmetrical) or anisotomous (unequal). Isotomous branches may be recurved, while anisotomous branches may become falcate (hooked), or cervicorn, if combined with twisting axes. Apical meristems of ''Dictyota'' species have been reported to be either truncate, rounded, or acute. A considerable degree of morphological plasticity has been observed from branching patterns, thus making molecular analyses indispensable when identifying species. Colors of living thalli range from dark brown to green (as in ''D. friabilis'') or blue (as in ''D. cyanoloma''). The thalli grow from apical cells which differentiate into an outer cortical and an inner medullary cell layer. Cortical cells on the margins of the thalli may grow into leaf-like projections or teeth (as in ''D. ciliolata'' and ''D. cyanoloma'') while adventitious branches may grow from the central cortical cells. Thalli may also grow hair (20-50 um in diameter). Thalli attach to the substrate via rhizoids which are multicellular, uniseriate, branching, and hyaline (glassy or transparent). Different species may have one or several attachment points which can lead to a wide range of growth forms (i.e. creeping thalli or fully erect). Dictyota-dichotoma-19880601-a

Internal anatomy

The thalli are

parenchyma Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word π ...

tous and are characterized by one or more apical cells that divide into an outer cortical and an inner medullary cell layer which can have several different configurations (e.g. uni-layered cortex with unilayered medulla, uni-layered cortex with multi-layered medulla, etc.).

Distribution

''Dictyota'' is distributed along tropical to temperate waters with species having generally restricted geographic ranges. It is the most abundant genus of brown algae in the Mediterranean Sea as well as the Atlantic coasts of Europe.

Ecology

Species of the genus are commonly found in subtidal to intertidal rocky pools. Seasonality in species' abundances as well as fertility are driven mainly by temperature, photoperiod, and solar radiation. For instance, populations of ''D. dichotoma'' in the southern hemisphere are highly abundant for a majority of the year but are largely absent in the warmer months, which is when its northern counterparts are most abundant and fertile.

Life History

''Dictyota'' exhibits an isomorphic life cycle wherein the alternating gametophyte and sporophyte phases appear morphologically similar. This alternation co-occurs with a change in ploidy. The gametophytes produce gametes which undergo fertilization to produce the diploid sporophyte, which then produces sporangia which will release 4 haploid spores through meiosis. Half of the haploid spores will develop into the female gametophytes while the other half will develop into male gametophytes, starting the process over again. ''Dictyota'' is

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

and reproduces both sexually and asexually. Release of gametes follows a diurnal and lunar periodicity. Gametes are often released 20–30 minutes after first light, with peaks occurring once or twice a month depending on the species. Asexual reproduction may occur via adventitious branching following the loss of the apical meristem.

Chemical Composition

''Dictyota'' is known to have high levels of fatty acids and lipids which makes the genus ideal for use as feedstock. The pigments found in ''Dictyota'' are Chlorophyll ''a'', ''c,'' fucoxanthin and violaxanthin which are present in a ratio of 13:3:10:1. This ratio may be altered by depth.

Exploitation/Utilization and Management

The genus is not currently cultivated nor harvested on an industrial scale. It is mainly exploited for its secondary metabolites which are known to have anticoagulant, antibacterial, anti-inflammatory properties, among others, making them useful for a wide range of pharmaceutical applications. For instance, there is evidence that methanolic extracts of ''Dictyota'' inhibits the butyrylcholinesterase (BuChE) enzyme in humans, which could potentially treat Alzheimer's disease. Other applications include its use as biofuel - due to the high lipid content of some species - and as supplemental feeds for poultry, cattle, and fish. A study in 2014 found that feeds with ''D. bartayresiana'' supplements could potentially reduce in vitro methane production of ruminants by 92.2%, which may have implications for reducing emissions from the agricultural sector.

Species

The genus ''Dictyota'' contains the following species:Guiry, M.D. & Guiry, G.M. (2018). AlgaeBase. World-wide electronic publication, National University of Ireland, Galway (taxonomic information republished from AlgaeBase with permission of M.D. Guiry). Dictyota J.V.Lamouroux, 1809. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=144086 on 2018-07-12M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org/search/genus/detail/?genus_id=oe101e7b01e405395 ; searched on 12 July 2018. *'' Dictyota acutiloba'' J.Agardh, 1848 *'' Dictyota adhaerens''

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, 1965 *'' Dictyota adnata'' Zanardini, 1878 **'' Dictyota adnata f. nana'' Post *'' Dictyota aegerrima'' ( Allender &

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, 2006 *'' Dictyota alternifida'' J.Agardh, 1894 *'' Dictyota anastomosans'' Steen et al. *'' Dictyota apiculata var. Agardh'' Weber-van Bosse *'' Dictyota asiatica'' I.K.Hwang *'' Dictyota attenuata'' P.Crouan & H.Crouan, 1842 *''

Dictyota bartayresiana ''Dictyota bartayresiana'', commonly known as a forded sea tumbleweed, is a species of brown alga found in the tropical western Indo-Pacific region and the Gulf of Mexico. It contains chemicals that are being researched for possible use as antimi ...

'' J.V.Lamouroux, 1809 **'' Dictyota bartayresiana var. divaricata'' Kützing *'' Dictyota bifurca'' J.Agardh, 1894 *'' Dictyota binghamiae'' J.Agardh, 1894 *'' Dictyota canaliculata'' O.De Clerck & E.Coppejans, 1997 *'' Dictyota canariensis'' ( Grunow) Tronholm, 2013 *''

Dictyota caribaea ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

'' Hörnig & Schnetter, 1992 **'' Dictyota cervicornis f. pseudodichotoma''

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Dictyota cervicornis f. spiralis ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

**'' Dictyota ceylanica var. anastomosans''

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*'' Dictyota chalchicueyecanensis'' Lozano-Orozco & Sentíes **''

Dictyota ciliata var. humilis ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals ( diterpenes) which have potential medicinal value. As at the end o ...

'' Grunow *''

Dictyota ciliolata ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals ( diterpenes) which have potential medicinal value. As at the end o ...

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Dictyota concrescens ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

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Dictyota coriacea ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

'' ( Holmes) I.K.Wang, H.-S.Kim & W.J.Lee, 2004 *''

Dictyota crenulata ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

'' J.Agardh, 1847 *''

Dictyota cribrosa ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

'' Setchell &

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, 1930 *''

Dictyota crinita ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals ( diterpenes) which have potential medicinal value. As at the end o ...

'' ( J.Agardh) Hörnig, Schnetter &

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, 1992 *'' Dictyota crux'' **'' Dictyota crux f. parva'' A.Bachmann *'' Dictyota cuneata'' Dickie, 1874 *''

Dictyota cyanoloma ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

'' Tronholm,

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, 2010 *'' Dictyota cymatophila'' Tronholm, M.Sanson & Afonso-Carrillo, 2010 *''

Dictyota decumbens ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals ( diterpenes) which have potential medicinal value. As at the end o ...

'' ( R.W.Ricker) Hörnig, Schnetter &

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Dictyota detergenda ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

, 2009 *'' Dictyota dhofarensis'' ( Nizamuddin & A.C.Campbell)

, 2006 *'' Dictyota dichotoma'' (

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) J.V.Lamouroux, 1809 *'' Dictyota dichotoma'' Suhr, 1839 **''

Dictyota dichotoma f. angustior ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

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Dictyota dichotoma var. fimbriata ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals ( diterpenes) which have potential medicinal value. As at the end o ...

'' Piccone & Grunow **'' Dictyota dichotoma var. genuina'' Grunow **''

Dictyota dichotoma var. guinea ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

'' Grunow **''

Dictyota dichotoma var. inequalis ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

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Dictyota dichotoma var. intricata ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

'' ( C.Agardh) Greville **''

Dictyota dichotoma var. patens ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

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Dictyota dichotoma f. proliferans ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

'' Ercegovic *'' Dictyota diemensis''

ex Kützing, 1859 *'' Dictyota dilatata''

, 1925 *'' Dictyota divaricata'' P.L.Crouan & H.M.Crouan, 1865 *'' Dictyota dolabellana'' De Paula, Yoneshigue-Valentin &

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, 2008 *'' Dictyota dumosa'' Børgesen, 1935 *''

Dictyota fasciculata ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

'' Sperk, 1869 *''

Dictyota fascida ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

'' J.Agardh, 1898 **'' Dictyota fasciola var. abyssinica'' J.Agardh *''

Dictyota fasciola ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

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) J.V.Lamouroux, 1809 **'' Dictyota fasciola var. divergens f. major''

**'' Dictyota fasciola var. divergens f. minor''

**'' Dictyota fasciola var. elongata'' De Notaris **'' Dictyota fasciola f. major''

**'' Dictyota fasciola f. minor''

**''

Dictyota fasciola var. repens ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

'' ( J.Agardh) Ardissone *'' Dictyota fastigiata''

, 1845 *''

Dictyota fenestrata ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

'' J.Agardh, 1894 *''

Dictyota flabellata ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end of ...

'' ( F.S.Collins) Setchell &

, 1924 *'' Dictyota flabellulata''

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& Schiel *'' Dictyota flagellifera''

, 2009 *'' Dictyota foliosa'' J.Agardh, 1892 *'' Dictyota friabilis'' Setchell, 1926 *'' Dictyota furcellata'' ( C.Agardh) Greville, 1830 *'' Dictyota galapagensis'' ( Farlow)

, 2006 *''

Dictyota grossedentata ''Dictyota'' is a genus of brown seaweed in the family Dictyotaceae. Species are predominantly found in tropical and subtropical seas, and are known to contain numerous chemicals (diterpenes) which have potential medicinal value. As at the end o ...

Coppejans Coppejans is a surname. Notable people with the surname include: *Kimmer Coppejans (born 1994), Belgian tennis player *Paul Coppejans (1933–2018), Belgian pole vaulter {{Short pages monitor