Dictyosphaeria

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Dictyosphaeria
Dictyosphaeria cavernosa.jpg
Scientific classification e
(unranked): Viridiplantae
Phylum: Chlorophyta
Class: Ulvophyceae
Order: Cladophorales
Family: Siphonocladaceae
Genus: Dictyosphaeria
Decaisne

Dictyosphaeria is a genus of green algae (class Ulvophyceae) in the family Siphonocladaceae.[1]

Taxonomy and nomenclature[]

The genus Dictyosphaeria belongs to the Order of Cladophorales; Family Siphonocladaceae. It comprises a total of 13 taxonomically recognized species that were based from available literatures. [2]

Taxonomically accepted species of Dictyosphaeria[]

  • Dictyosphaeria australis Setchell
  • Dictyosphaeria cavernosa (Forsskål) Børgesen
  • Dictyosphaeria enteromorpha Montagne & Millardet
  • Dictyosphaeria intermedia Weber Bosse
  • Dictyosphaeria mutica Yamada
  • Dictyosphaeria ocellata (M.Howe) Olsen-Stojkovich
  • Dictyosphaeria sericea Harvey
  • Dictyosphaeria spinifera C.K.Tseng & C.F.Chang
  • Dictyosphaeria ulvacea Kützing
  • Dictyosphaeria valonioides Zanardini
  • Dictyosphaeria versluysii Weber Bosse (Figure 1)
Fig. 1. Habit of Dictyosphaeria versluysii attached in a rocky substrate.

General morphological description[]

Thalli[]

The thalli are composed of visibly hollow hexagonal or polygonal cells; and are monostromatic or polystromatic depending on species. They can be solid or button-shaped at around 1-5 cm; and spherical and club-shaped at 1 cm or more. The size of each cells are around 300 - 500 µm in diameter. Complex rhizoidal system is absent, however, basal cells are firmly attached to the substratum. [3]

The coloration of the macroalgae varies from grass green to bluish. [4]

Cells[]

Cells are visible to the naked eye. They are minutely determinate, simple or furcate, and tenacular that are structurally cushioned together. Occasionally, tenacular cells may also function as adventitious rhizoids.

Cells are multinucleated and have numerous discoid chloroplasts. Chloroplasts bear single pyrenoid surrounded by starch sheath and divided to two or more portions by traversing thylakoids.

Life history[]

The life history of Dictyosphaeria is both biphasic and isomporphic alternation of generation. This involves zoospores that are quadriflagellate, as well as isogamous and biflagellate gametes. Asexual reproduction through thalli fragmentation and possible parthenogenesis of gametes which result in smooth surface thalli textures.

Mitotic division and cytokinesis were observed in the development of the zoospores. The mitotic spindle is placed centrally at the early course of the zooid differentiation. Prophase nuclei with centrioles is present during this stage only. Other mitotic stages are observed together in the network cytoplasm [5]

Distribution and Habitat[]

The genus Dictyosphaeria is widely found in the tropical region. Its habitat varies from shallow intertidal habitats, such as coral rubbles, to reef flats where they can be the dominant macroalgae. They are commonly found attached to rocky substrate or coral rubble (Figure 2).

Economic Use/ Natural Products[]

The genus Dictyosphaeria, particularly the species D. cavernosa is used for fish bait and animal feed; as well as antimicrobial medicine for human application. [6]


Natural products were also extracted from the genus Dictyosphaeria that can be utilized for both scientific and medical applications. Novel metabolites such as, Dictyosphaerin, a bicyclic lipid compound were extracted from Dictyosphaeria sericea.[7] In addition, the seaweed genus also harbors microorganisms such as the fungal species belonging to the genus Penicillium. A study has shown that isolated fungal specimens from the species Dictyosphaeria versluysii were found to produce novel metabolites: two (2) polyketides - dictyosphaeric acids A and B, including the well-known anthraquinone carviolin.[8]

Fig. 2. . Dictyosphaeria versluysii attached to a rocky substrate beside a coral. Photo taken at Patar, Pangasinan, Philippines.

Anthropogenic Impacts[]

In the Kaneohe Bay in Hawaii, USA, they are considered as invasive species resulted from continuous discharge of nutrient wastes from coastal communities, as well as reduction in herbivore (such as from fish) pressures in the area [9] As early as the year 1970, reduced coral cover and increased spatial expansion of Dictyosphaeria cavernosa were already documented in the Kaneohe bay area.[10] However, simultaneous population growth and watershed development in the bay were already began before the 1960s, including the phase shift on the bay's reef systems. This indicates that successful growths of the macroalgae may already initiated years earlier.


References[]

  1. ^ See the NCBI webpage on Dictyosphaeria. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. Retrieved 2007-03-19.
  2. ^ "Algaebase :: Listing the World's Algae". www.algaebase.org. Retrieved 2021-12-03.
  3. ^ "Algaebase :: Listing the World's Algae". www.algaebase.org. Retrieved 2021-12-01.
  4. ^ "Dictyosphaeria cavernosa". www.hawaii.edu. Retrieved 2021-12-03.
  5. ^ Hori, T., and Enomoto, S. (1978). "Developmental Cytology of Dictyosphaeria cavernosa. II. Nuclear Division during Zooid Formation". Botanica Marina. 21: 477–481 – via De Gruyter.CS1 maint: multiple names: authors list (link)
  6. ^ Trono, Jr., Gavino C. (1997). Field Guide & Atlas of the Seaweed Resources of the Philippines. Makati City, Philippines: Bookmark Inc. ISBN 971-569-252-4.
  7. ^ Rochfort, S.J., Watson, R., and Capon, R.J. (1996). "Dictyosphaerin: A Novel Bicyclic Lipid from a Southern Australia Marine Green Algae, Dictyosphaeria sericea". Journal of Natural Products. 59: 1154–1156 – via ASC Publication.CS1 maint: multiple names: authors list (link)
  8. ^ Bugni, T.S., Janso, J.E., Williamson, R.T., Feng, X., Bernan, V.S., Greenstein, M., Carter, G.T., Maiese, W.M., and Ireland, C.M. (2004). "Dictyospaeric Acids A and B: New Decalactones from an Undescribed Penicillium sp. Obtained from the Alga Dictyosphaeria versluysii". Journal of Natural Products. 67: 1396–1399 – via ACS Publication.CS1 maint: multiple names: authors list (link)
  9. ^ Stimson, J., Larned, S.T., and Conklin, E. (2001). "Effects of herbivory, nutrient levels, and introduced algae on the distribution and abundance of the invasive macroalga Dictyosphaeria cavernosa in Kanoehe Bay, Hawaii" (PDF). Coral Reefs. 19: 343–357 – via Springer Link.CS1 maint: multiple names: authors list (link)
  10. ^ Banner, A.H., and Bailey, J. (1970). Technical Report 50: The effects of urban pollution upon a coral reef system, a preliminary report. Honolulu: Hawaii Institute of Marine Biology. p. 66.CS1 maint: multiple names: authors list (link)

External links[]

  1. https://www.algaebase.org/search/genus/detail/?genus_id=35942
  2. https://www.hawaii.edu/reefalgae/invasive_algae/chloro/dictyosphaeria_cavernosa.htm
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