''Chattonella'' is a genus of the marine class

raphidophyte The raphidophytes, formally known as Raphidophycidae or Raphidophyceae (formerly referred to as Chloromonadophyceae and Chloromonadineae), are a small group of eukaryotic algae that includes both marine and freshwater species. All raphidophytes ...

s associated with red tides and can be found in the phylum Heterokontophyta in

stramenopile The stramenopiles, also called heterokonts, are protists distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flagella, in some they are attached to other areas of the cellular surface, an ...

s. These unicellular

flagellate A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and the ...

s are found in brackish ecosystems. The genus ''Chattonella'' is composed of five species: ''C. subsalsa'', ''C. antiqua'', ''C. marina'', ''C. minima'', and ''C. ovata''.

Structure and synthesis

The ''Chattonella'' species contain an ectoplasm with vacuoles, chloroplasts, and mucocysts and an

endoplasm Endoplasm, also known as entoplasm, generally refers to the inner (often granulated), dense part of a cell's cytoplasm. This is opposed to the ectoplasm (cell biology), ectoplasm which is the outer (non-granulated) layer of the cytoplasm, which ...

with a nucleus and other organelles. Due to their lack of cell wall, these species have the ability to change size and shape. Therefore, fish populations cannot recognize the toxins and cannot defend themselves. Each species of the ''Chattonella'' genus is very similar or identical in DNA sequencing. ''C. minima'' has an identical morphological structure to ''C. antiqua'', so researchers are developing ways to search for the gene responsible for differentiating between the different ''Chattonella'' strains. The only currently known difference between the two strains is the number of chromosomes; ''C. minima'' contains 90-110 chromosomes while ''C. marina'' contains 29 chromosomes. ''Chattonella'' algal blooms synthesis is compared to "diatom resting hypothesis" with the only major difference being that ''Chattonella'' cysts can germinate in the dark as opposed to

diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

s which can germinate only in sunlight. Factors such as water temperature, salinity, irradiance, and nutrients each contribute to the growth of ''Chattonella''.

Environmental impact

Algal species can be beneficial, neutral, or harmful to environmental ecosystems. Three of these species, ''C. antiqua'', ''C. marina'', and ''C. ovata,'' contribute the growing problem of

harmful algal bloom A harmful algal bloom (HAB), or excessive algae growth, sometimes called a red tide in marine environments, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, water deoxygenation, ...

s (HAB). ''Chattonella'' outbreaks are known to be enhanced by

eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

. ''C. verruculosa'' was originally categorized with these toxic species, but further

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analysis showed it actually belonged to class

Dictyochophyceae Dictyochophyceae sensu lato is a photosynthetic lineage of heterokont The stramenopiles, also called heterokonts, are protists distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flage ...

, not

Raphidophyceae The raphidophytes, formally known as Raphidophycidae or Raphidophyceae (formerly referred to as Chloromonadophyceae and Chloromonadineae), are a small group of eukaryotic algae that includes both marine and freshwater species. All raphidophyte ...

. These harmful algal species trigger the

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

of gill cells in fish. More specifically, the toxins produce reactive oxygen species that disrupt oxygen transport and ultimately lead to suffocation. Fish species such as ''Thunnus maccoyii'', ''Seriola quinqueradiata'', and others are declining rapidly in Australia, Japan, India, China, Brazil, Mexico, and USA, greatly affecting fishing industries. As HABs become more common, more research is dedicated to preventing these outbreaks.

Analysis methods

To prevent ''Chattonella'' HABs, the individual species must first be studied. A technique using

monoclonal antibodies A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a Lineage (evolution), cell lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Mon ...

can be used to identify the genus, while the

RAPD RAPD may refer to: * Relative afferent pupillary defect *Random amplification of polymorphic DNA Random amplified polymorphic DNA (RAPD), pronounced "rapid", is a type of polymerase chain reaction (PCR), but the segments of DNA that are amplified ...

reaction can be used to distinguish between different species within the genus. Other researchers use PCR-RFLP is also used to identify species of ''Chattonella''. They sequence ITS rDNA and rRNA, and

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

of the species to try to target the highly variable regions with molecular markers. Inverted optical microscopes and scanning electron microscopes (SEM) are also used to compare cell size and structure of different ''Chattonella'' species.

References

{{Taxonbar, from=Q5087960 Ochrophyte genera Ochrophyta