''Caulerpa racemosa'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of edible

green alga The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

, a

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

Caulerpaceae Caulerpaceae is a family of green algae in the order Bryopsidales Bryopsidales is an order of green algae, in the class Ulvophyceae. Characteristics The thallus is filamentous and much branched and may be packed into a mass. It is coenocyti ...

. It is commonly known as sea grapes (along with the related ''

Caulerpa lentillifera ''Caulerpa lentillifera'' is a species of ulvophyte green algae from coastal regions in the Asia-Pacific. This seaweed is one of the favored species of edible ''Caulerpa'' due to its soft and succulent texture. It is traditionally eaten in th ...

'') and is found in many areas of shallow sea around the world. There are a number of different forms and varieties, and one that appeared in the Mediterranean Sea in 1990, which is giving cause for concern as an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

Taxonomy

There are about 75 species of ''Caulerpa''. Many of them exhibit polymorphism, showing different growth forms in different habitats which makes them difficult to identify. ''C. racemosa'', ''C. laetevirens'' and ''C. peltata'' form a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

. A number of forms and varieties for ''C. racemosa'' are listed but further study is needed to clarify their exact

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

relationships.

Description

A plant of ''C. racemosa'' consists of a number of branches linked to

stolon In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external s ...

s which are anchored to the sandy substrate by

rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be uni ...

s. The branches are a few centimetres apart and can grow to a height of . Many spherical or ovate side-shoots branch off these and give the seaweed its name of sea grapes.Sea grapes (''Caulerpa racemosa'')
''Marine Species Identification Portal''. Retrieved 2011-08-20. Like other members of the order

Bryopsidales Bryopsidales is an order of green algae, in the class Ulvophyceae. Characteristics The thallus is filamentous and much branched and may be packed into a mass. It is coenocytic, having multi-nucleate cells consisting of cytoplasm contained withi ...

, each ''C. racemosa'' plant consists of a single enormous cell with a large number of nuclei. The

chloroplast A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in ...

s containing

chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...

are free to migrate from any part of the organism to another and there is a network of fibrous proteins that helps movement of

organelle In cell biology, an organelle is a specialized subunit, usually within a cell, that has a specific function. The name ''organelle'' comes from the idea that these structures are parts of cells, as organs are to the body, hence ''organelle,'' the ...

s.The Cell Biology of the Bryopsidales
Retrieved 2011-08-18

Distribution

''C. racemosa'' is widely distributed in shallow temperate and tropical seas. In 1926 a new form of the alga was reported off

Tunisia ) , image_map = Tunisia location (orthographic projection).svg , map_caption = Location of Tunisia in northern Africa , image_map2 = , capital = Tunis , largest_city = capital , ...

, possibly an immigrant from the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

, and this later spread to much of the eastern

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

. In 1990, a new, larger form with two vertical rows of branches on opposite sides of the stem was found off

Libya Libya (; ar, ليبيا, Lībiyā), officially the State of Libya ( ar, دولة ليبيا, Dawlat Lībiyā), is a country in the Maghreb region in North Africa. It is bordered by the Mediterranean Sea to the north, Egypt to Egypt–Libya bo ...

. It spread widely, invading much of the Mediterranean Sea and becoming more widespread than the invasive species, ''

Caulerpa taxifolia ''Caulerpa taxifolia'' is a species of green seaweed, an alga of the genus ''Caulerpa'', native to tropical waters of the Pacific Ocean, Indian Ocean, and Caribbean Sea. The species name ''taxifolia'' arises from the resemblance of its leaf-like ...

''. It is known as var. ''cylindracea'' and may have originated from Australian waters. In America ''C. racemosa'' is found in shallow water in the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

, around

Bermuda ) , anthem = "God Save the King" , song_type = National song , song = " Hail to Bermuda" , image_map = , map_caption = , image_map2 = , mapsize2 = , map_caption2 = , subdivision_type = Sovereign state , subdivision_name = , e ...

and along the eastern seaboard of America from

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Biology

In the Mediterranean, growth begins in April when new stolons develop and erect branches start growing, and continue till December, after which the plants decline and become dormant.Grazing on ''Caulerpa racemosa'' var. ''cylindracea'' (Caulerpales, Chlorophyta) in the Mediterranean Sea by herbivorous fishes and sea urchins.
Retrieved 2011-08-22. ''C. racemosa'' reproduces

vegetatively Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is any form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or spec ...

by fragmentation. When pieces of the plant get broken off they develop into new plants. Small pieces of tissue only a few millimetres across are capable of doing this. ''C. racemosa'' can also reproduce sexually and in so doing exhibits holocarpy. This means that all the organism's

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

is used up in the creation of the

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce t ...

s and only a husk remains at the site of the original plant. The plants are

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

with male and female gametes being produced by the same plant and liberated into the water column where they unite to give spherical

zygote A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellula ...

s. These settle and after five weeks produce

germ tube A germ tube is an outgrowth produced by spores of spore-releasing fungi during germination. The germ tube differentiates, grows, and develops by mitosis to create somatic hyphae.C.J. Alexopolous, Charles W. Mims, M. Blackwell, ''Introductory My ...

s which elongate and branch to develop into new plants. Mass spawnings sometimes take place in the

and normally do so just before dawn. There were 39 such mass spawnings during a period of 125 days and the days on which they took place showed no relation to the tidal or lunar cycles. The gametes remain motile for about 60 minutes. Mass spawning is advantageous to the plant in increasing the chances of fertilisation. Underwater visibility can be reduced to less than one metre by the green cloud produced in the process. Similar mass spawnings take place in the Mediterranean Sea causing a cloud of green gametes to be released in the water approximately 14 minutes before sunrise.

Ecology

''Caulerpa'' species contain secondary metabolites that are

cytotoxic Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are an immune cell or some types of venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa''). Cell physiology Treating cells ...

, of which caulerpenyne is the most abundant. These deter animals from consuming the plants. A study has been done on

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

s that graze on meadows of the invasive '' C. cylindracea'' in the north west of its range in the Mediterranean. The

sea bream The Sparidae are a family of fish in the order Perciformes, commonly called sea breams and porgies. The sheepshead, scup, and red seabream are species in this family. Most sparids are deep-bodied compressed fish with a small mouth separated by a ...

s ''

Boops boops ''Boops boops'' (; from Ancient Greek , literally 'cow-eye'), commonly called the bogue, is a species of seabream native to the eastern Atlantic. Its common name in most languages refers to its large ("bug") eyes. Distribution and habitat The sp ...

'' and ''

Sarpa salpa ''Sarpa salpa'', known commonly as the dreamfish, salema, salema porgy, cow bream or goldline, is a species of sea bream, recognisable by the golden stripes that run down the length of its body, and which can cause ichthyoallyeinotoxism when ea ...

'' were found to feed on the algae, as did the

sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

s ''

Paracentrotus lividus ''Paracentrotus lividus'' is a species of sea urchin in the family Parechinidae commonly known as the purple sea urchin. It is the type species of the genus and occurs in the Mediterranean Sea and eastern Atlantic Ocean. Description ''Paracent ...

'' and ''

Sphaerechinus granularis ''Sphaerechinus granularis'' is a species of sea urchin in the family Toxopneustidae, commonly known as the violet sea urchin, or sometimes the purple sea urchin (though the latter is also a common name for a Pacific sea urchin ''Strongylocentr ...

''. Other

s also grazed occasionally, but the total amount consumed was compensated for by the rapid growth of the plant and it was considered that these organisms were not likely to play a valuable role in bio-control of the plant. ''C. taxifolia'' and ''C. racemosa'' show the great influence of substratum on their spatial distribution with a high colonization of the dead matte of the seagrass ''Posidonia oceanica'' ''C. racemosa'' and '' C. taxifolia'' are both invasive Lessepsian migrants. Caulerpenyne content is lesser in ''C. racemosa'' than in ''C. taxifolia''.

Uses

Like the closely related '' C. lentillifera'', ''C. racemosa'' is edible. It is consumed widely in salads in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists ...

, the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

, and

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

. It is also eaten by local fishermen in

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

and

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

. They are rich in fiber, proteins, minerals (calcium and magnesium),

folic acid Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and ...

ascorbic acid Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...

vitamin A Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably bet ...

, and

vitamin B1 Thiamine, also known as thiamin and vitamin B1, is a vitamin, an essential micronutrient, that cannot be made in the body. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosphorylated forms of thia ...

while also being low in fat. In addition to the nutritional qualities of ''C. racemosa'', it also has anti bacterial and anti-oxidant properties but these characteristics are not yet fully explored. These different biological activities provide a glimpse of biomedical innovations for the future. The properties are believed to come from a strain of rare

endophytic An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life cycle without causing apparent disease. Endophytes are ubiquitous and have been found in all species of plants studied to date; h ...

actinomycetes The Actinomycetales is an order of Actinomycetota. A member of the order is often called an actinomycete. Actinomycetales are generally gram-positive and anaerobic and have mycelia in a filamentous and branching growth pattern. Some actinomycete ...

that lives in

symbiosis Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

with ''C. racemosa'' and more particularly of the

secondary metabolites Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the nor ...

produced (

flavonoids Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

and

alkaloids Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar st ...

). Extracts of ''C. racemosa'' are already tested to reduce different types of

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

but also to fight against

multi-drug resistant Multiple drug resistance (MDR), multidrug resistance or multiresistance is antimicrobial resistance shown by a species of microorganism to at least one antimicrobial drug in three or more antimicrobial categories. Antimicrobial categories ar ...

uropathogens (as '' K. Pneumoniae'' and ''

P. aeruginosa P. is an abbreviation or acronym that may refer to: * Page (paper), where the abbreviation comes from Latin ''pagina'' * Paris Herbarium, at the ''Muséum national d'histoire naturelle'' * ''Pani'' (Polish), translating as Mrs. * The ''Pacific Repo ...

''). The multi drug resistance is a major public health problem because by 2050 (World Health Organization WHO), 10 million people could die each year as a result of this evolution of bacteria against the current families of

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...

. Moreover, a multitude of potential treatments for various pathologies have been identified, particularly for

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

and

herpes Herpes simplex is a viral infection caused by the herpes simplex virus. Infections are categorized based on the part of the body infected. Oral herpes involves the face or mouth. It may result in small blisters in groups often called cold s ...

References

{{Taxonbar, from=Q1147907 racemosa Species described in 1873