Brachionus calyciflorus

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Brachionus calyciflorus
Brachionuscalyciflorus.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Rotifera
Class: Monogononta
Order: Ploima
Family: Brachionidae
Genus: Brachionus
Species:
B. calyciflorus
Binomial name
Brachionus calyciflorus
Pallas, 1766

Brachionus calyciflorus is a planktonic rotifer species occurring in freshwater. It is commonly used as a model organism in toxicology, ecology and evolutionary biology.
Its advantages include the small size and short generation time (average generation time of B. calyciflorus is around 2.2 days at 24 °C).

Contents

Taxonomy

The taxonomy of Brachionus calyciflorus is well-established based on morphological and molecular characteristics. As a member of the phylum Rotifera, it shares many features with other rotifers, including a ciliated corona and a characteristic rotary motion. Within the genus Brachionus, there are several species, including B. plicatilis, which is also commonly used in research and aquaculture. Brachionus calyciflorus is distinct from other species in the genus due to its unique calyx-shaped lorica.

Morphology

Brachionus calyciflorus has a characteristic morphology that distinguishes it from other rotifer species. The body of Brachionus calyciflorus is elongated and cylindrical in shape, measuring about 160 to 350 μm in length and 80 to 160 μm in width. The head region of the body is retractable and contains a characteristic ring of cilia, called the corona, which is used for feeding and locomotion. The corona is composed of two types of cilia, the large frontal cilia and smaller ventral cilia.

One of the most distinctive features of Brachionus calyciflorus is its lorica, or outer shell. The lorica of Brachionus calyciflorus is formed from two separate plates, with the upper plate forming a calyx-like structure over the head region of the body. The lower plate is elliptical in shape and covers the rest of the body. The lorica provides structural support and protection to the rotifer.

Brachionus calyciflorus has a well-developed digestive system, with an elongated pharynx and a muscular stomach. The reproductive system of the rotifer is also well-developed, with a pair of ovaries and testes located in the posterior part of the body.

Overall, the distinctive morphology of Brachionus calyciflorus plays an important role in its feeding, locomotion, reproduction, and adaptation to its aquatic environment.

Life Cycle

The life cycle of Brachionus calyciflorus begins with the hatching of eggs, which are either fertilized or produced by parthenogenesis. The juveniles that hatch from these eggs, called "amictic" females, are diploid and develop into reproductive females without undergoing meiosis, meaning that they produce clones of themselves.

Once the food supply becomes scarce, some amictic females switch to a meiotic mode of reproduction, producing haploid male offspring. These males then fertilize the haploid eggs, laid by the female offspring, leading to the production of diploid resting eggs, which remain dormant in the sediment until the environmental conditions become suitable for hatching. In response to suitable environmental conditions, the resting eggs hatch into diploid amictic females, starting a new cycle.

However, when the food supply remains abundant, the amictic females continue to reproduce asexually, producing new clones of themselves through multiple generations, leading to high population densities.

During the life cycle of Brachionus calyciflorus, there are several stages and instars, including neonate, juvenile, pre-adult, and adult stages. The duration of each stage can vary depending on environmental factors such as temperature, food supply, and population density. In ideal conditions, the life cycle of Brachionus calyciflorus can be as short as 2–3 days.

Habitat and Distribution

Brachionus calyciflorus is a freshwater rotifer species that is widely distributed around the world. It is commonly found in a range of freshwater environments, including ponds, lakes, streams, and rivers.

This species is euryhaline, meaning it can tolerate a wide range of salinities, and can be found in both fresh and brackish water habitats. It can also tolerate various environmental conditions such as pH, water temperature, and oxygen levels.

Brachionus calyciflorus is a cosmopolitan species, meaning it is found in many regions of the world, including North and South America, Europe, Asia, Australia, and Africa. It has been reported in a range of countries, including the United States, Canada, Brazil, Spain, France, Sweden, Russia, and Japan.

In addition to its natural distribution, Brachionus calyciflorus is commonly used in aquaculture, where it is reared in laboratory cultures to feed fish and other aquatic organisms. It is also used in ecotoxicology studies as a test organism due to its short life cycle and sensitivity to environmental pollutants.

Importance

Brachionus calyciforus is an important zooplankton species that plays a significant role in freshwater ecosystems. Here are some of the reasons why:

  1. Food source: Brachionus calyciflorus is an important food source for many aquatic organisms such as fish, amphibians, and invertebrates. It is also used as a live food for aquarium fish.
  2. Studying environmental changes: Brachionus calyciflorus can serve as an indicator of environmental changes in water bodies. Monitoring population dynamics of Brachionus calyciflorus can help assess the health of aquatic systems and detect any changes that may occur as a result of pollution or climate change.
  3. Toxicity testing: Brachionus calyciflorus is widely used in ecotoxicological studies due to its sensitivity to toxic substances. It is used to test the effects of different substances on aquatic organisms, and to assess the potential risk to human health and the environment.
  4. Bioremediation: Brachionus calyciflorus is known to feed on harmful algae and bacteria that can cause water quality issues. As a result, it is considered a potential agent for bioremediation of polluted water bodies.

In summary, Brachionus calyciflorus has ecological, scientific, and potential biotechnological importance.

Culturing

Culturing Brachionus calyciflorus involves growing this species of rotifer in a controlled environment. Here are some important factors to consider when culturing Brachionus calyciflorus:

  1. Culture vessel: Brachionus calyciflorus can be cultured in a variety of vessels such as laboratory-grade glassware, plastic containers, and aquariums. The culture vessel should be clean and have a large surface area to promote growth.
  2. Temperature: The optimal temperature for culturing Brachionus calyciflorus is between 20 °C to 28 °C. Higher temperatures can lead to a decrease in growth rate and reproduction, while lower temperatures can lead to a decrease in overall biomass.
  3. Light: Brachionus calyciflorus requires a light source with a 12-hour light and dark cycle. Illumination can be artificial or natural, with a light intensity of 2,000 to 4,000 lux.
  4. Feeding: Brachionus calyciflorus feeds on microalgae and bacteria, and thus, it is important to provide a food source. Some commonly used microalgae for Brachionus calyciflorus cultivation include Chlorella vulgaris, Scenedesmus sp., and Nannochloropsis sp.
  5. Water quality: The pH of culture water for Brachionus calyciflorus should be maintained between 6.5 and 7.5, and the salinity level should be between 0.5 and 5 parts per thousand.
  6. Harvesting: Brachionus calyciflorus can be harvested using a fine-mesh filter or by centrifugation. The harvested rotifers can then be used as a live food source for other aquatic organisms or as a sample for experiments.

In summary, culturing Brachionus calyciflorus requires careful maintenance of optimal temperature, lighting, feeding, water quality, and harvesting to ensure consistent growth and high biomass production.

Reproduction

Brachionus calyciflorus normally reproduces by cyclical parthenogenesis. [1]
Transitions to obligate parthenogenesis have been described. Obligate parthenogens were homozygous for a recessive allele, which caused inability to respond to the chemical signals that normally induce sexual reproduction in this species. [2]

Species complex

Like the Brachionus plicatilis cryptic species complex Brachionus calyciflorus seems also to be a species complex consisting of more than one species. [3] [4]

Related Research Articles

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Aquaculture, also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants. Aquaculture involves cultivating freshwater, brackish water and saltwater populations under controlled or semi-natural conditions, and can be contrasted with commercial fishing, which is the harvesting of wild fish. Mariculture, commonly known as marine farming, is aquaculture in seawater habitats and lagoons, as opposed to freshwater aquaculture. Pisciculture is a type of aquaculture that consists of fish farming to obtain fish products as food.

<span class="mw-page-title-main">Asexual reproduction</span> Reproduction without a sexual process

Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the full set of genes of their single parent and thus the newly created individual is genetically and physically similar to the parent or an exact clone of the parent. Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and bacteria. Many eukaryotic organisms including plants, animals, and fungi can also reproduce asexually. In vertebrates, the most common form of asexual reproduction is parthenogenesis, which is typically used as an alternative to sexual reproduction in times when reproductive opportunities are limited. Komodo dragons and some monitor lizards can reproduce asexually.

<span class="mw-page-title-main">Rotifer</span> Phylum of pseudocoelomate invertebrates

The rotifers, commonly called wheel animals or wheel animalcules, make up a phylum of microscopic and near-microscopic pseudocoelomate animals.

<i>Daphnia</i> Genus of crustaceans

Daphnia is a genus of small planktonic crustaceans, 0.2–6.0 mm (0.01–0.24 in) in length. Daphnia are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembles the movements of fleas. Daphnia spp. live in various aquatic environments ranging from acidic swamps to freshwater lakes and ponds.

<span class="mw-page-title-main">Bdelloidea</span> Class of parthenogenetic freshwater rotifers

Bdelloidea is a class of rotifers found in freshwater habitats all over the world. There are over 450 described species of bdelloid rotifers, distinguished from each other mainly on the basis of morphology. The main characteristics that distinguish bdelloids from related groups of rotifers are exclusively parthenogenetic reproduction and the ability to survive in dry, harsh environments by entering a state of desiccation-induced dormancy (anhydrobiosis) at any life stage. They are often referred to as "ancient asexuals" due to their unique asexual history that spans back to over 25 million years ago through fossil evidence. Bdelloid rotifers are microscopic organisms, typically between 150 and 700 µm in length. Most are slightly too small to be seen with the naked eye, but appear as tiny white dots through even a weak hand lens, especially in bright light. In June 2021, biologists reported the restoration of bdelloid rotifers after being frozen for 24,000 years in the Siberian permafrost.

<span class="mw-page-title-main">Mysida</span> Small, shrimp-like crustacean

Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this pouch and are not free-swimming characterises the order. The mysid's head bears a pair of stalked eyes and two pairs of antennae. The thorax consists of eight segments each bearing branching limbs, the whole concealed beneath a protective carapace and the abdomen has six segments and usually further small limbs.

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<span class="mw-page-title-main">Fish hatchery</span> Aquaculture facility

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<i>Brachionus</i> Genus of rotifers

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<span class="mw-page-title-main">Ecotoxicity</span>

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<i>Brachionus plicatilis</i>

Brachionus plicatilis is a euryhaline rotifer in the family Brachionidae, and is possibly the only commercially important rotifer, being raised in the aquaculture industry as food for fish larvae. It has a broad distribution in salt lakes around the world and has become a model system for studies in ecology and evolution.

Sea sponge aquaculture is the process of farming sea sponges under controlled conditions. It has been conducted in the world's oceans for centuries using a number of aquaculture techniques. There are many factors such as light, salinity, pH, dissolved oxygen and the accumulation of waste products that influence the growth rate of sponges. The benefits of sea sponge aquaculture are realised as a result of its ease of establishment, minimum infrastructure requirements and the potential to be used as a source of income for populations living in developing countries. Sea sponges are produced on a commercial scale to be used as bath sponges or to extract biologically active compounds which are found in certain sponge species. Techniques such as the rope and mesh bag method are used to culture sponges independently or within an integrated multi-trophic aquaculture system setting. One of the only true sustainable sea sponges cultivated in the world occur in the region of Micronesia, with a number of growing and production methods used to ensure and maintain the continued sustainability of these farmed species.

<i>Keratella cochlearis</i>

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Adineta ricciae is a species of freshwater rotifers in the family Adinetidae. It was first described in 2005 after being discovered by chance in dry mud beside a billabong in Australia. It is used as a model organism as it is easy to keep in culture.

<i>Floscularia ringens</i> Species of rotifers

Floscularia ringens is a species of rotifer belonging to the class Monogononta, which resides in a tube that it builds using many little circular pellets consisting of bacteria and small pieces of detritus.

<i>Cothurnia</i> Genus of protozoans belonging to peritrich ciliates

Cothurnia is a genus of freshwater and marine peritrichs in the family Vaginicolidae. It is characterised by living in a transparent tubular lorica. During the feeding or vegetative phase of its life cycle, Cothurnia attaches to submerged surfaces through a short stalk — mostly on the surfaces of fishes, crustaceans and aquatic plants. It is commonly studied for its epibiotic relationship with the host that it is attached to.

<i>Daphnia pulicaria</i> Species of small freshwater animal

Daphnia pulicaria is a species of freshwater crustaceans found within the genus of Daphnia, which are often called "water fleas," and they are commonly used as model organisms for scientific research. Like other species of Daphnia, they reproduce via cyclic parthenogenesis. D. pulicaria are filter-feeders with a diet primarily consisting of algae, including Ankistrodesmus falcatus, and they can be found in deep lakes located in temperate climates. Furthermore, D. pulicaria are ecologically important herbivorous zooplankton, which help control algal populations and are a source of food for some fish. D. pulicaria are closely related to Daphnia pulex, and numerous studies have investigated the nature and strength of this relationship because these species can produce Daphnia pulex-pulicaria hybrids. In recent years, D. pulicaria along with other Daphnia species have been negatively affected by invasive predators, such as Bythotrephes longimanus.

<span class="mw-page-title-main">Brachionidae</span> Family of rotifers

Brachionidae is a family of rotifers belonging to the order Ploima. Species are found in freshwater and marine habitats.

References

  1. "Brachionus calyciflorus | Marine Rotifera". rotifera.lifedesks.org. Archived from the original on 23 December 2014. Retrieved 6 June 2022.
  2. C.-P. Stelzer, J. Schmidt, A. Wiedlroither, and S. Riss (2010). Loss of Sexual Reproduction and Dwarfing in a Small Metazoan. PLoS ONE 5(9): e12854.
  3. Brachionus calyciflorus is a species complex: mating behavior and genetic differentiation among four geographically isolated strains JJ Gilbert, EJ Walsh - Rotifera X, 2005 - Springer
  4. Spatial patterns of genetic differentiation in Brachionus calyciflorus species complex collected from East China in summer XL Xiang, YL Xi, XL Wen, JY Zhang, Q Ma - Hydrobiologia, 2010 - Springer

Sources