• Source: Lobophora (alga)

Lobophora is a genus of thalloid brown seaweed of the Phylum Ochrophyta; Class Phaeophyceae.




Taxonomy and nomenclature


The genus Lobophora belongs to the Order Dictyotales; Family Dictyotaceae, and additionally to the Tribe of Zonarieae.
Currently, there are a total of seventy-one (71) taxonomically accepted species belonging to this genus:

Lobophora abaculusa C.W.Vieira, Payri & De Clerck
Lobophora abscondita C.W.Vieira, Payri & De Clerck
Lobophora adpressa O.Camacho & C.Fernández-García
Lobophora africana C.W.Vieira & M.Zubia
Lobophora agardhii Payri & C.W.Vieira
Lobophora antsirananaensis Viera & Rasoamanendrika
Lobophora asiatica Z.Sun, Ji.Tanaka & H.Kawai
Lobophora astrolabeae C.W.Vieira & Payri
Lobophora bandeirae C.W.Vieira, DeClerk & F.Leliaert
Lobophora boudeuseae C.W.Vieira & Payri
Lobophora boussoleae C.W.Vieira & Payri
Lobophora brooksii D.L.Ballantine & J.N.Norris
Lobophora caboverdeana C.W.Vieira & C.H.Almada
Lobophora canariensis (Sauvageau) C.W.Vieira, De Clerck & Payri
Lobophora ceylanica (Harvey ex E.S.Barton) C.W.Vieira, De Clerck & Payri
Lobophora challengeriae C.W.Vieira
Lobophora colombiana O.Comacho & Fredericq
Lobophora coquilleae C.W.Vieira
Lobophora crispata O.Camacho & Fredericq
Lobophora dagamae C.W.Viera
Lobophora delicata Camacho & Fredericq
Lobophora dichotoma (R.H.Simons) P.C.Silva
Lobophora dickiei Payri & C.W.Vieira
Lobophora dimorpha C.W.Vieira, Payri & De Clerck
Lobophora dispersa Camacho, Freshwater & Fredericq
Lobophora endeavouriae C.W.Vieira
Lobophora erythraea C.W.Vieira
Lobophora esperanceae C.W.Vieira
Lobophora etoileae C.W.Vieira
Lobophora evanii C.W.Vieira & Rasoamanendrika
Lobophora flabellata C.W.Vieira, De Clerck, R.J.Anderson & J.J.Bolton
Lobophora garyi C.W.Vieira & Rasoamanendrika
Lobophora gibbera C.W.Vieira, Payri & De Clerck
Lobophora gloriosa C.W.Vieira & M.Zubia
Lobophora hederacea C.W.Vieira, Payri & De Clerck
Lobophora henae C.W.Vieira & Rasoamanendrika
Lobophora indica V.Krishnamurthy & M.Baluswami
Lobophora variegata var. indica Umamaheswara Rao
Lobophora isselii (Piccone & Grunow) C.W.Vieira, De Clerck & Payri
Lobophora kimiae C.W.Vieira & Rasoamanendrika
Lobophora lamourouxii Payri & C.W.Vieira
Lobophora lessepsiana C.W.Vieira
Lobophora lubaoreniana Luan Rixiao & Ding Lanping
Lobophora madagascariensis C.W.Vieira & Rasoamanendrika
Lobophora maldivensis C.W.Vieira & C.Payri
Lobophora minima V.Krishnamurthy & M.Baluswami
Lobophora variegata var. minima Umamaheswara Rao
Lobophora monticola C.W.Vieira, Payri & De Clerck
Lobophora nigrescens J.Agardh
Lobophora novae C.W.Vieira & M.Zubia
Lobophora obscura (Dickie) C.W.Vieira, De Clerck & Payri
Lobophora pachyventera Z.Sun, P.-E.Lim, Ji.Tanaka & H.Kawai
Lobophora pacifica (Setchell) C.W.Vieira, De Clerck & Payri
Lobophora panamensis O.Camacho, C.Fernández-García & Fredericq
Lobophora papenfussii (W.R.Taylor) Farghaly
Lobophora petila C.W.Vieira, Payri & De Clerck
Lobophora providenceae C.W.Vieira
Lobophora rechercheae C.W.Vieira
Lobophora richardii C.W.Vieira & Payri
Lobophora rickeri Kraft
Lobophora rosacea C.W.Vieira, Payri & De Clerck
Lobophora schneideri C.W.Vieira
Lobophora setchellii C.W.Vieira & Payri
Lobophora soaresii CW.Vieira & F.A.Rasoamanendrika
Lobophora sonderi C.W.Vieira, De Clerck & Payri
Lobophora tortugensis O.Camancho & Fredericq
Lobophora tsengii D.Tien & Z.Sun
Lobophora undulata C.W.Vieira, Payri & De Clerck
Lobophora variegata (J.V.Lamouroux) Womersley ex E.C.Oliveira
Lobophora zmaragdina C.W.Vieira & C.Payri




General morphological characteristics






= Thalli

=
Thalli are foliose or fan-shaped and possess different growth morphologies: decumbent, procumbent, crustose, conk-like (shelf-like), fasciculate, and stipitate, depending on species and habitat. Thalli arises from matted rhizoidal holdfast with branched fronds displaying broadly flabellate to irregularly branched forms. Algal hairs are arranged in concentric lines or scattered turf. Size can reach up to 20 cm long. Coloration are commonly light brown to dark-brown.




= Cellular structure (internal morphology)

=
Thalli is 7-12 cells thick, with the outermost layers composed of cortical cells overlying innermost layer of larger medullary cells. Medullary cells usually exhibit uniform sized except for the larger central cells. Discoid chloroplasts are found at the cortical layers.




= Reproductive structures

=
The sporangial sori of Lobophora are either scattered or in concentric bands found at the surface of the thallus They are characteristically indusiated but without paraphyses. Sporangia without a basal stalk cell produce up to eight (8) spores. Oogonia are found in sori on both side of the frond surfaces.




Life history


The life history of Lobophora is currently unknown. But it may have similar stages with other members from Dictyotaceae Family.




Distribution and habitat


The genus Lobophora are found throughout the pantropical and even temperate regions. They are found growing on solid substrate (rocks) at intertidal (some are wave-exposed) to subtidal areas of rocky-reef habitats.




Ecology and impacts


Seaweeds, such as Lobophora are naturally occurring in coral reefs. Under normal conditions, the interactions between Genus Lobophora and corals pose no threat and can co-exist in an ecosystem. This is attributed to the control of algal populations by coral chemical defense and herbivory. However, when these contributing control factors become unbalanced, Lobophora and other associated seaweeds become opportunistic in taking over reefs (i.e. increasing spatial cover) and by density-dependent negative feedback, prevents corals from settling on substrate. However, as mentioned earlier, Lobophora a species-rich group and certain individuals have different growth patterns, interactions, and habitat-preferences. Understanding and determining its taxa is utmost important.
Because of capacity of seaweeds, such as Lobophora to occupy large spatial habitats, particularly in degraded reefs, they can have an impact on the chances of coral larvae to settle on a substrate. Lobophora can inhibit coral settlement, however, its effect can decrease later on life history stages because they have no effect on growing coral nubbins. Chances of coral larvae to settle in degraded reef followed by disturbance may be challenging.
As mentioned, Lobophora are highly preferred by herbivores particularly fish. Growth morphological defenses have been developed by this group to become unpalatable to its herbivores. Encrust (crustose) forming Lobophora, such as L. variegata are dominant in areas with high concentration of herbivorous fish and sea urchin, compare to other seaweeds having a foliose or decumbent morphologies. This indicates that high herbivory activities in the area may influence the defense mechanisms of seaweeds, in the case of Lobophora, its specific growth morphologies.

Varying metabolomic concentration differs from Lobophora species when exposed to changing natural habitats and substrates. Fatty acids derivatives and polyolefins were identified as chemomarkers of these changing conditions. This indicates possible chemical plasticity of metabolites in the genus. Different Lobophora may composed varying natural products depending on bioregion.




Economic importance/ natural products


Similar to other seaweeds, Genus Lobophora has a variety of natural products. There are: Minerals: cadmium (Cd), copper (Cu), mercury (Hg), iodine (I), nickel (Ni), lead (Pb), and zinc (Zn); Pigments: carotene, chlorophyll a, chlorophyll c, fucoxanthin; Polysaccharides/ simple sugars: alginic acid, laminarin; Sugar alcohol: mannitol.
In addition Lobophora may have contributions in medicinal application. Sulfated polysaccharides, fucans, from algae Lobophora variegata were shown to have anti-inflammatory activity in acute zymosan-induced arthritis in laboratory rats. It resulted in treatments by reducing cell infiltration in the synovial membrane with a decrease in TNF-α. It was also shown that heterofucans are strong antioxidants. Another is Lobophora has antiprotozoal activity against parasitic protozoans such as Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. Extract from L. variegata shows promising result in the treatments of protozoan infection. The chloroform fraction of the extract contained a major sulfoquinovosyldiacylglycerol (SQDG), identified as 1-O-palmitoyl-2-O-myristoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol, together with small amounts of 1,2-di-O-palmitoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol, and a new compound identified as 1-O-palmitoyl-2-O-oleoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol were identified having strong antiprotozoal attributes.




References

Kata Kunci Pencarian:

• Lobophora (alga)
• Lobophora
• Lobophora variegata
• Dictyotales
• Asterochloris
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• Mustafa Shameel
• Hydroclathrus
• List of seaweeds and marine flowering plants of Australia (temperate waters)