Carageen | |
---|---|
A-D Chondrus crispus ; E-F Mastocarpus stellatus | |
Scientific classification | |
(unranked): | Archaeplastida |
Division: | Rhodophyta |
Class: | Florideophyceae |
Order: | Gigartinales |
Family: | Phyllophoraceae |
Genus: | Mastocarpus |
Species: | M. stellatus |
Binomial name | |
Mastocarpus stellatus (Stackhouse) Guiry | |
Synonyms | |
Gigartina stellata |
Mastocarpus stellatus, commonly known as carrageenan moss or false Irish moss, [1] is a species in the Rhodophyceae division, a red algae seaweed division, and the Phyllophoracea family. M. stellatus is closely related to Irish Moss (Chondrus crispus). It grows in the intertidal zone. It is most collected in North Atlantic regions such as Ireland and Scotland, together with Irish moss, dried, and sold for cooking and as the basis for a drink reputed to ward off colds and flu. Marine biologists have completed studies on the medicinal reputation of M. stellatus to discover the full potential of its pharmaceutical benefits. Additionally, marine biologists have conducted research on its potential to serve as an alternative to plastic. The application of M. stellatus in these different industries is correlated with the seaweed's adaptations which developed in response to the environmental stressors present around its location on the rocky intertidal.
It grows from a discoid holdfast stipe, and the fronds are channeled unlike those of Chondrus crispus, which are flat. It grows to a height of 10–20 cm (3.9–7.9 in) and branches dichotomously. The frond is cartilaginous and reddish-brown in colour, with a greenish or purplish tinge. The mature algae show reproductive structures which develop on erect filaments up to 1 mm (0.039 in) in diameter, these make it readily distinguishable from Chondrus crispus. In colour it is reddish brown, purple or bleached. [2] [3]
M. stellatus occurs commonly on rocks in the mid and lower-intertidal. It is generally found on all coasts of Ireland and Britain, except perhaps for parts of the east of England: Lincoln, Norfolk and Suffolk. [4] Other recorded locations include: Iceland, Faeroes, North Russia to Rio de Oro, Canada (Newfoundland) to U.S. (North Carolina). [3] Mastocarpus stellatus is able to coexist with C. crispus on the northern New England coast despite being a competitive inferior to C. crispus. A greater tolerance for freezing allows it to exist above C. crispus in northern environments where freezing stresses are significant. M. stellatus is rarely found south of Cape Cod on the United States Atlantic coast because it is out competed by C. crispus when the freezing tolerances are lower.[ citation needed ]
M. stellatus is morphologically similar to Chondrus crispus. Both species endure high levels of environmental stress from freezing temperatures, desiccation, high light, and hyper or hypo-osmotic shock. The degree of stress placed on the algae by these factors varies depending on the time of year and latitude. These stressors result in the production of reactive oxygen; large amounts of reactive oxygen around the algae can damage the organisms’ DNA, proteins, and lipids. [5]
To defend against excessive production of reactive oxygen, these organisms use antioxidants to reduce oxygen levels. Compared to C. crispus, M. stellatus’ location on the rocky intertidal experiences greater fluctuations in environmental stressors. M. stellatus was found to have higher levels of oxygen metabolism and a faster decomposition rate than C. crispus. Additionally, M. stellatus makes use of scavenging enzymes including: catalase, superoxide dismutase, glutathione reductase, and ascorbate peroxidase (to scavenge hydrogen peroxide). After conducting his research on M. stellatus and C. crispus in 1999, Jonas Collén argued that the difference between the species may be an evolutionary adaptation by adopting different strategies to cope with environmental stressors at differing intertidal zones and locations. [5] M. stellatus showed responses to changes to tidal height with changes in oxygen metabolism, suggesting that the increase in this enzyme activity (which produces a higher content of soluble protein to break down reactive oxygen compounds) requires energy allocation to these enzymes in order to adapt stress tolerance. [5]
In 1979, Michael Guiry and John A. West conducted a study and determined that M. stellatus exhibits two distinct biological life cycles and reproduction processes; the first type being heteromorphic and the second being direct. [6] M. stellatuses exhibiting the heteromorphic-type life history are dioecious plants (in a broad sense) that reproduce sexually by alternating diploid crustose tetrasporophytes with foliose gametophytes. M. stellatus that have direct-type life histories reproduce asexually because fertilization never occurred. This results in the production of carpospores by the female gametophytes, resulting in the growth of foliose plants that lack tetrasporangia. [7] Tetrasporangia are pivotal in sexual reproduction because, through meiosis, they create four unique tetraspores as male or female gametes. [8] Since M. stellatus that produce asexually do not develop tetrasporangia, they are "genetically isolated" from sexually producing M. stellatus. [7]
The earliest record of collecting Irish seaweed is evidenced by 12th century poems by monks, according to Michael Guiry. In a 2001 market analysis of Irish seaweed aquaculture, the estimated combined annual national seaweed harvest of M. stellatus and C. crispus was less than 100 tonnes. [9] M. stellatus is harvested during the gametophyte life phase because later phases, with more sulphated carrageenan, are harder to remove from its rock. The food and pharmaceutical industries are interested in the seaweed for their antioxidant, anticoagulant, and thickening or gelling properties. Antioxidant and anticoagulant properties are determined by sulfation, molecular weight, location of sulfate groups, sugar composition, and glycosidic branching. [10] In addition to its health properties and applications, the gelling properties of M. stellatus can create a biodegradable film that may be a sustainable and edible alternative to plastics for food preservation and functional food development. [1]
Carrageen is the active polysaccharide compound that is responsible for the mechanisms that give the plant its antioxidant, anticoagulant, and gelling properties. The process of extracting the carrageenan from the M. stellatus usually consists of boiling the plant for several hours and using ethanolic precipitation to isolate the compound. Researchers found that the concentration of carrageen substance and efficiency of properties is dependent on the extraction conditions including boiling temperatures, drying methods, and dilution techniques. These compounds were used to create films to determine how chemical structures and biological reactions can be manipulated to produce beneficial levels of elasticity, durability, solubility, water resistance, and thickness required for an effective alternative to food packaging. [1] Their findings suggest that higher concentrations of sulfate and proteins in the carrageenan reinforces the molecular structure, increases thickness, increases elasticity, and prevents water filtration, making the gel stronger. However, the strength between these bonds causes a concentration of force at their intersection which makes it easier to break. More studies must be conducted to test for more factors of M. stellatus and degrees of property efficacy. [1]
Carrageenan, or phycocolloids are sulfated linear polysaccharides composed of carrageenan and carrageenan precursors. In order for carrageenan compounds to be useful, the kappa and/or iota carrageenan need to be isolated from its mu-carrageenan or nu-carrageenan precursors. [1] [ jargon ] Lower molecular weight and higher amounts of sulfate results in higher antioxidant properties. Heavier molecular weight and higher amounts of sulfate result in anticoagulant properties. The relationships between antioxidant and anticoagulant mechanisms suggest that inflammation and coagulation are interconnected and interdependent processes in M. stellatus. [10] M. stellatus has been used in home remedies to treat coughs, colds, and sore throats by mixing it with C. crispus and other herbs, spices, and sweeteners. [11]
Chondrus crispus—commonly called Irish moss or carrageenan moss —is a species of red algae which grows abundantly along the rocky parts of the Atlantic coasts of Europe and North America. In its fresh condition it is soft and cartilaginous, varying in color from a greenish-yellow, through red, to a dark purple or purplish-brown. The principal constituent is a mucilaginous body, made of the polysaccharide carrageenan, which constitutes 55% of its dry weight. The organism also consists of nearly 10% dry weight protein and about 15% dry weight mineral matter, and is rich in iodine and sulfur. When softened in water it has a sea-like odour. Because of the abundant cell wall polysaccharides, it will form a jelly when boiled, containing from 20 to 100 times its weight of water.
Carrageenans or carrageenins are a family of natural linear sulfated polysaccharides that are extracted from red edible seaweeds. Carrageenans are widely used in the food industry, for their gelling, thickening, and stabilizing properties. Their main application is in dairy and meat products, due to their strong binding to food proteins. In recent years, carrageenans have emerged as a promising candidate in tissue engineering and regenerative medicine applications as they resemble native glycosaminoglycans (GAGs). They have been mainly used for tissue engineering, wound coverage, and drug delivery.
Colpomenia is a genus of brown macroalgae in the family Scytosiphonaceae.
Udotea is a genus of green algae in the family Udoteaceae.
Gelidium amansii, also known as umutgasari, is an economically important species of red algae commonly found and harvested in the shallow coast of many East Asian countries including North and South Korea, China, Japan, Singapore, and northeast Taiwan. G. amansii is an important food source in East Asian countries and has been shown to have medicinal effects on dieting. Hence, in folklore medicine G. amansii is used to treat constipation. This algae is used to make agar, whose components are the polysaccharide agarose and agaropectin, from the large amount of algin which is located in the algae's cell wall, as well it is sometimes served as part of a salad, puddings, jams, and other culinary dishes in producing regions. Agar is a gelatinous substance that is commercially used both as an ingredient in gelatinous desserts and as an incubation matrix for microbes and other products that require an ecologically friendly gelatinous matrix. G. amansii can be purple, red, to yellowish-red because it contains the class of pigments known as phycobiliprotein. Its branching body is cartilaginous and can grow up to a height of 8 to 30 cm or 3 to 12 in. G. amansii may have four or five opposite, compound-lobed, pinnate leaves on each branch. It is uniaxial with an apical cell and whorled cells coming from the axial towards the exterior of the algae. The pith is compacted with apical cells and the epidermis is formed by rounded whorled cells. G. amansii is being studied as a cheap biofuel.
Kappaphycus alvarezii, the elkhorn sea moss, is a species of red algae. The elkhorn sea moss varies in size, weight, and age. It is a dark greenish-brown hue and can sometimes be deep purple. The moss is cylindrical in shape throughout the seaweed. Its diameter averages 1.526 mm when dried. Near the base of the seaweed, its average length is from 1 mm to 17 mm and 1 mm to 2 mm in diameter. Firm algae are around 2 m tall, with axes and branches around 1–2 cm in diameter. It used to be believed they reproduced through vegetative fermentation, but recent studies show that they reproduce sexually. They reproduce through vegetative propagation and reproduce sexually. Cross sections of the Elkhorn sea moss have a medulla composed of small thick-walled cells interspaced among large parenchyma cells. This moss is used for various types of foods that humans consume and can also be used to make a jelly-like dessert. This moss is a very good source of minerals and of high commercial interest. It is one of the most important commercial sources of carrageenans, a family of gel-forming, viscosifying polysaccharides. Farming methods affect the character of the carrageenan that can be extracted from the seaweed. It is very fast-growing, known to double its biomass in 15 days.
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 kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; other species, such as planktonic algae, play a vital role in capturing carbon, producing at least 50% of Earth's oxygen.
Red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats but relatively rare in freshwaters. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations found in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, there are no terrestrial species, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity.
Edible seaweed, or sea vegetables, are seaweeds that can be eaten and used for culinary purposes. They typically contain high amounts of fiber. They may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae. Seaweeds are also harvested or cultivated for the extraction of polysaccharides such as alginate, agar and carrageenan, gelatinous substances collectively known as hydrocolloids or phycocolloids. Hydrocolloids have attained commercial significance, especially in food production as food additives. The food industry exploits the gelling, water-retention, emulsifying and other physical properties of these hydrocolloids.
Chondrus is a genus of red algae containing 11 accepted species:
Hydroclathrus is a genus of perforate brown alga, of the phylum Ochrophyta and the class Phaeophyceae.
Amphiroa is a genus of thalloid red algae under the family Corallinaceae.
Hypnea is a genus of red algae, and a well known carrageenophyte.
Furcellaria is a genus of red algae. It is a monotypic genus, the only species being Furcellaria lumbricalis, which has commercial importance as a raw material for carrageenan production. It is mainly harvested from the waters of Denmark and Canada.
Elsie Conway was a British phycologist. She served as president of the British Phycological Society from 1965 to 1967, and was one of the earliest women Fellows of the Royal Society of Edinburgh.
Caulerpa cupressoides, commonly known as cactus tree alga, is a species of seaweed in the Caulerpaceae family. Green alge of Caulerpa genus are salty and pungent in style and are consumed by several marine cultures around the world.
Melobesia membranacea is a small marine alga encrusting on the surface of other algae. In the division of the Rhodophyta.
Mastocarpus papillatus, sometimes called Turkish washcloth, black tar spot, or grapestone is a species of red algae in the family Phyllophoraceae. It is sometimes confused with the distantly related Turkish towel which is of a similar texture but larger. The specific epithet papillatus is due to the nipple-like projections on the female gametophyte which can give the texture of a terrycloth washcloth found at a Turkish bath.
Hildenbrandia rubra is a marine species of thalloid red alga. It forms thin reddish crusts on rocks and pebbles in the intertidal zone and the shallow subtidal zone. It is a common species with a cosmopolitan distribution, and is able to tolerate a wide range of conditions.
Sphacelaria is a genus of brown macroalgae in the family Sphacelariaceae.