''Tetraspora'' is a genus of
green algae in the family
Tetrasporaceae
The Tetrasporaceae are a family of green algae, specifically of the Chlamydomonadales.See the NCBIbr>webpage on Tetrasporaceae Data extracted from the
Genera
, AlgaeBase
AlgaeBase is a global species database of information on all groups ...
of the order
Chlamydomonadales
Chlamydomonadales, also known as Volvocales, are an order of flagellated or pseudociliated green algae, specifically of the Chlorophyceae.See the NCBIbr>webpage on Chlamydomonadales Data extracted from the Chlamydomonadales can form planar or ...
, division
Chlorophyta
Chlorophyta or Prasinophyta is a taxon of green algae informally called chlorophytes. The name is used in two very different senses, so care is needed to determine the use by a particular author. In older classification systems, it refers to a ...
.
Species of ''Tetraspora'' are unicellular green algae that exist in arrangements of four and consist of cells being packaged together in a gelatinous envelope that creates macroscopic colonies.
These are primarily freshwater organisms, although there have been few cases where they have been found inhabiting marine environments and even contaminated water bodies. ''Tetraspora'' species can be found all around the globe, with the exception of Antarctica.
Despite the ubiquitous presence, greatest growth of the genera's species is seen in the
polar climatic zones.
''Tetraspora'' species are non-motile
and instead of having flagella, they possess pairs of pseudoflagella which are part of the
pseudociliary apparatus.
On average the cell diameter of ''Tetraspora'' ranges from 6-13 μm.
Energy is accumulated via photosynthesis through two cup-shaped chloroplasts, making the species
primary producer
Primary or primaries may refer to:
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* Primary (band), from Australia
* Primary (musician), hip hop musician and record producer from South Korea
* Primary Music, Israeli record label
Works
* ...
s.
Blooms have been noted in contaminated environments due to excess augmentation of ammonia from industrial waste and are now being associated with the drop in biodiversity in such water bodies.
Both sexual and asexual reproduction are possible for species within this genus. In addition, mitosis is well defined in ''Tetraspora'' species; particularly investigated in ''T. gelatinosa''. Cell division involves elaborate arrangement of
microtubules, basal body complexes and involve the use of structures like
phycoplast image:Phycoplast.png, Schematic representation of types of cytokinesis in the green algae: 1) Phycoplast formation with cleavage furrow (e.g. ''Chlamydomonas''); 2) Cleavage furrow and persistent telophase spindle (e.g. ''Klebsormidium''); 3) Phycop ...
s and
protoplast.
Studies have shown antimicrobial properties of certain species. In addition, ''Tetraspora'' is an important photobiological hydrogen producers and therefore is intensively being looked at for
biofuel purposes.
, thirty species have been classified into this genus.
Etymology
The genus name ''Tetraspora'' is derived from the word tetrad; which refers to the confirmation of four. ''Tetra'' is Greek for four and ''spora'' is Latin for cells, thus describing species of this genus as existing in groups of four.
History
The genus ''Tetraspora'' was first described by Link ex Desvaux in the year 1818, where the purpose for the genus was to organize algae with spores arranged in confirmations of tetrads.
In the very first classifications, species of ''Tetraspora'' were classified into the order
Tetrasporales under
Chlorophyta
Chlorophyta or Prasinophyta is a taxon of green algae informally called chlorophytes. The name is used in two very different senses, so care is needed to determine the use by a particular author. In older classification systems, it refers to a ...
.
However, with molecular analysis, it was found that ''Tetraspora'' species had similar basal body morphology to ''
Chlamydomonas''
and also had molecular similarity in the SSU rDNA. This changed the classification from being under the order Tetrasporales to order
Chlamydomonadales
Chlamydomonadales, also known as Volvocales, are an order of flagellated or pseudociliated green algae, specifically of the Chlorophyceae.See the NCBIbr>webpage on Chlamydomonadales Data extracted from the Chlamydomonadales can form planar or ...
[ (or Volvocales]), where they still reside today.
Habitat
''Tetraspora'' species are primarily freshwater organisms which inhabit ecosystems like streams, lakes, rivers, ponds. They can be found in harsh environments like thermal effluents and industrial waste. However, just recently it has been found that ''Tetraspora'' species have the ability to adapt and reside in marine environments that are exceptionally nutrient rich and receive freshwater river outflows. Species have been found in both stagnant and free flowing water bodies, although morphology of species between the two water types slightly differs. Physio-chemical studies of the habitats have shown that ''Tetraspora'' species tolerate wide pH ranges: (4.5-9.63) but are most commonly found in water bodies with a pH between 6–7. Likewise, the optimal growth conditions for species of the genus ''Tetraspora'' are alkaline, low mesotrophic and shallow bodies of freshwater. Interestingly, species have also shown to be most abundant and well established on the beds of slow-flowing streams and rivers; where they generally take on the form of thin filamentous macroscopic colonies.
''Tetraspora'' species are found on every continent, with the exception of Antarctica, and can be located at all latitudes. Therefore, they are found in all climatic zones: polar, tropics, warm and cool temperate zones and the equatorial zones. While they can be present in all climatic zones, the most optimal zones are cool temperate and the polar zones. This is because of the species preferring cold water to warm.
Ecology
Like most other green algae, ''Tetraspora'' also is photoautotrophic Photoautotrophs are organisms that use light energy and inorganic carbon to produce organic materials. Eukaryotic photoautotrophs absorb energy through the chlorophyll molecules in their chloroplasts while prokaryotic photoautotrophs use chlorophyll ...
. Their ability to conduct photosynthesis, establishes them at the starting point of aquatic food chains and food webs. ''Tetraspora'' function as primary producer
Primary or primaries may refer to:
Arts, entertainment, and media Music Groups and labels
* Primary (band), from Australia
* Primary (musician), hip hop musician and record producer from South Korea
* Primary Music, Israeli record label
Works
* ...
s and hence are responsible for capturing and assimilating the energy that will be passed down subsequent trophic levels.
In water bodies associated with sewage waste, industrial waste and fishery waste, ''Tetraspora'' blooms have been documented. Spewing of sewage, industrial and fishery wastes leads to anthropogenic eutrophication
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...
, where there is excess augmentation of ammonia; a principal nitrogen source for certain species of ''Tetraspora''. The excess nitrogen is proposed to contribute to uncontrolled cell proliferation of ''Tetraspora'' colonies; resulting in algal blooms. ''Tetraspora'' blooms have negative effects on the overall environmental ecology because they shift and alter the chemical properties of the water. This is because with the mass growth, hypoxia and/or anoxia can occur and these may have detrimental effects on biodiversity and survivability of other organisms such as fish.
Morphology
Species of the genus ''Tetraspora'' are unicellular green algae, in which the individual cells are non-motile and are shaped spherically or elliptically. These individual cells are arranged in sets or multiples of four; these could be in the arrangement of four-by-four cells or two-by-two. All cells are encased within a macroscopic mucilaginous matrix, that creates macroscopic colonies. Within the envelope, the cells are uniformly distributed and overall, the mucilaginous envelope creates an irregular outline with asymmetrical shapes and edges.
The size of cells has been found to vary based on the type of ''Tetraspora'' species and the type of climatic zone the species is found in. On average the diameter of species in the genus ''Tetraspora'' ranges from 6-13 μm, with the species in the tropics usually being the smallest (6-9 μm), followed by the temperate zone species (6-14 μm), and the polar species (7.5-13 μm). The difference in cell size therefore also impacts sizes of the colonies, but sizes of colonies also vary with whether the cells are residing in stagnant or flowing water. In stagnant water, colonies may range from 5–10 cm in length, while in flowing water, colonies may reach lengths up to 50 cm. In addition to impacting colony size, the type of water (stagnant or free flowing) also impacts the morphology of the colonies. Most macroscopic colonies of ''Tetraspora'' are cylindrical in nature, but in stagnant water colonies may appear as short sacs and clubs with thalli
Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were ...
that resemble balloons. Flowing water colonies on the other hand, tend to form narrow cylindrical structures with the thalli also being more or less cylindrical and sometimes can be lightly rounded at the sheaths.
Cellular structures/anatomy
Species in the genus ''Tetraspora'' contain two pseduoflagella as a part of the pseudociliary apparatus, two cup-shaped chloroplasts with chlorophyll A and B pigments, a single pyrenoid
Pyrenoids are sub-cellular micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. Annu. Rev. Plant Bio ...
and contractile vacuoles located inside the cytoplasm. Additionally, starch grains can be seen covering the pyrenoid and the walls of the cells are noted to be thin.
''Tetraspora'' species do not possess a flagellum
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates.
A microorganism may have f ...
of the 9+2 microtubular fibre configuration, instead they have pseudoflagellum with a 9+0 fibre confirmation; where the central two tubular fibres are absent. There are two pseduoflagelulla that exist in a pair and both protrude from the anterior region of the cell and into the gelatinous matrix. Additionally, it has been found that the pseudoflagella are longer than the actual cells. The pseudoflagella is part of the pseudociliary apparatus, which consists of a cytoplasmic microtubule system, striated fibre system, basal bodies, and the pseudoflagella themselves. Pseudoflagella each display a striped pattern, where they are seen to regularly have striped structures of light and dark sections of equal length. On average, the length of pseudoflagella is from 70 to 120 μm long and 0.70-1.60 μm wide, but they can get up to 155 μm in length.
Life cycle
Reproduction in the genus ''Tetraspora'' can be both sexual and asexual. Sexual reproduction occurs through isogamous means, but occasionally depending on the species, it can also be isogamous or oogamous
Oogamy is an extreme form of anisogamy where the gametes differ in both size and form.
In oogamy the large female gamete (also known as ovum) is immobile, while the small male gamete (also known as sperm) is mobile. Oogamy is a common form of an ...
. Asexual division in ''Tetraspora'' occurs via mitotic division; the products can be two or four uninucleate daughter cells. In addition to vegetative cells, asexual reproduction can also produce zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves.
Diversity Flagella types
Zoospores may possess one or ...
s, which may act as autospore
An autospore is a non-motile (non-flagellated) aplanospore that is produced within a parent cell, and has the same shape as the parent cell, before release. Autospores, in addition to zoospore and aplanospore, are one of the three types of spore ...
s ranging from two to eight per cell.
When living conditions become less favourable, many species of the genus ''Tetraspora'' also have the ability to form into hypanospores called akineties. Akineties are thick-walled spores that are brown in colour with a diameter of 12.9-15.80 μm and a cell wall thickness of 0.6-1.10 μm. They function as resting cells which are resistant to cold temperatures and desiccation. The process of division of mature akineties is done by amoeboid protoplasts located inside the mucilaginous envelopes.
Cell division in ''Tetraspora'' species has been described. It is noted that prior to mitosis beginning, cells become immotile and the basal bodies located at the surface of cells start to retreat in. This causes the preprophase
Preprophase is an additional phase during mitosis in plant cells that does not occur in other eukaryotes such as animals or fungi. It precedes prophase and is characterized by two distinct events:
#The formation of the preprophase band, a dense ...
nucleus to migrate toward retreating basal body complex, around which microtubules start to gather. The basal body complex arranges itself to be closely associated with one pole of the cell, creating a mitotic spindle known as open polar fenestrae. Furthermore, it is speculated that the spindle itself may also be unicentric. Eventually, microtubules extend from the spindle, and during anaphase
Anaphase () is the stage of mitosis after the process of metaphase, when replicated chromosomes are split and the newly-copied chromosomes (daughter chromatids) are moved to opposite poles of the cell. Chromosomes also reach their overall maxim ...
, they penetrate through the fenestra
A fenestra (fenestration; plural fenestrae or fenestrations) is any small opening or pore, commonly used as a term in the biological sciences. It is the Latin word for "window", and is used in various fields to describe a pore in an anatomical st ...
e and split the nucleus. Subsequently, to telophase, the nucleus reforms, but a phycoplast image:Phycoplast.png, Schematic representation of types of cytokinesis in the green algae: 1) Phycoplast formation with cleavage furrow (e.g. ''Chlamydomonas''); 2) Cleavage furrow and persistent telophase spindle (e.g. ''Klebsormidium''); 3) Phycop ...
forms. In addition, a protoplast is found inside the cell wall and is noted to rotate within the wall during cleavage; a process known to occur by the cell undergoing furrowing.
Practical importance
Phytotoxic and cytotoxic activity analysis of some ''Tetraspora'' species displayed antibiotic activities against specific fungal and bacterial species, meaning that ''Tetraspora'' species may help develop or compose antibiotics. In addition, species of ''Tetraspora'' are known to be high hydrogen producing organisms. This is significant because hydrogen gas is considered a promising clean fuel. This means that ''Tetraspora'' species may potentially act as photobiological hydrogen producers and green biofuels.
References
External links
Scientific references
Scientific databases
AlgaeBase
AlgaTerra database
Index Nominum Genericorum
{{Taxonbar, from=Q7706742
Chlamydomonadales genera
Chlamydomonadales