| Prototheca | |
|---|---|
 | |
Scientific classification  | |
| Clade: | Viridiplantae |
| Division: | Chlorophyta |
| Class: | Trebouxiophyceae |
| Order: | Chlorellales |
| Family: | Chlorellaceae |
| Genus: | Prototheca Krüger, 1894 [1] |
| Species [2] | |
Prototheca is a genus of algae in the family Chlorellaceae. [3] While this genus is a member of the green algae, all Prototheca no longer have chloroplasts and therefore their photosynthetic ability. Some species can cause protothecosis in humans and various vertebrates.
From the Greek proto- (first) + thēkē (sheath), Prototheca is a genus of variably shaped spherical cells of achloric algae in the family Chlorellaceae. Wilhelm Krüger, a German expert in plant physiology and sugar production, reported Prototheca microorganisms in 1894, shortly after spending 7 years in Java studying sugarcane. He isolated Prototheca species from the sap of 3 tree species. Krüger named these organisms as P. moriformis and P. zopfii, the second name as a tribute to Friedrich Wilhelm Zopf, a renowned botanist, mycologist, and lichenologist. [4]
Although Prototheca lack chloroplasts, they were recognized early on as closely related to other Chlorellaceae based on other morphological and physiological traits similar to the group. [5] [6] Phylogenetics confirm that Prototheca species are closely related to Chlorella and other genera, although it is not yet clear whether Prototheca is a monophyletic group. [7]
With the lack of chloroplasts and photosynthetic ability, Prototheca grow heterotrophically and some exhibit parasitism. Other groups of photosynthetic organisms have undergone similar functional losses in photosynthetic ability and shifted to a parasitic lifestyle, such as in apicomplexans.
Some species in the genus Prototheca are known to cause protothecosis, one of the few researched diseases caused by algae, which are categorized as Algaemia. P. wickerhamii is the main causing agent of protothecosis in humans, and was first identified as such in 1964. P. zopfii is known to cause this disease in cattle and dogs.[ citation needed ]
Symptoms include: Cutaneous lesions, Olecranon bursitis.
A chloroplast is a type of organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. Chloroplasts have a high concentration of chlorophyll pigments which capture the energy from sunlight and convert it to chemical energy and release oxygen. The chemical energy created is then used to make sugar and other organic molecules from carbon dioxide in a process called the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in some unicellular algae, up to 100 in plants like Arabidopsis and wheat.
Chlorophyta is a division of green algae informally called chlorophytes.
A plastid is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. Plastids are considered to be intracellular endosymbiotic cyanobacteria.
The green algae are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as a sister of the Zygnematophyceae. Since the realization that the Embryophytes emerged within the green algae, some authors are starting to include them. The completed clade that includes both green algae and embryophytes is monophyletic and is referred to as the clade Viridiplantae and as the kingdom Plantae. The green algae include unicellular and colonial flagellates, most with two flagella per cell, as well as various colonial, coccoid (spherical), and filamentous forms, and macroscopic, multicellular seaweeds. There are about 22,000 species of green algae, many of which live most of their lives as single cells, while other species form coenobia (colonies), long filaments, or highly differentiated macroscopic seaweeds.
Viridiplantae is a clade of around 450,000–500,000 species of eukaryotic organisms, most of which obtain their energy by photosynthesis. The green plants are chloroplast-bearing autotrophs that play important primary production roles in both terrestrial and aquatic ecosystems. They include green algae, which are primarily aquatic, and the land plants (embryophytes), which emerged within freshwater green algae. Green algae traditionally excludes the land plants, rendering them a paraphyletic group, however it is cladistically accurate to think of land plants as a special clade of green algae that evolved to thrive on dry lands. Since the realization that the embryophytes emerged from within the green algae, some authors are starting to include them.
The Archaeplastida are a major group of eukaryotes, comprising the photoautotrophic red algae (Rhodophyta), green algae, land plants, and the minor group glaucophytes. It also includes the non-photosynthetic lineage Rhodelphidia, a predatorial (eukaryotrophic) flagellate that is sister to the Rhodophyta, and probably the microscopic picozoans. The Archaeplastida have chloroplasts that are surrounded by two membranes, suggesting that they were acquired directly through a single endosymbiosis event by phagocytosis of a cyanobacterium. All other groups which have chloroplasts, besides the amoeboid genus Paulinella, have chloroplasts surrounded by three or four membranes, suggesting they were acquired secondarily from red or green algae. Unlike red and green algae, glaucophytes have never been involved in secondary endosymbiosis events.
Selenastraceae is a family of green algae in the order Sphaeropleales. Members of this family are common components of the phytoplankton in freshwater habitats worldwide. A few species have been found in brackish and marine habitats, such as in the Baltic Sea.
Bryopsis, often referred to a hair algae, is a genus of marine green algae in the family Bryopsidaceae. Species in the genus are macroscopic, siphonous marine green algae that are made up of units of single tubular filaments. They can form dense tufts up to 40 cm in height. Each cell is made of up an erect thallus that is often branched into pinnules. Approximately 60 species have been identified in this genus since its initial discovery in 1809. The ecological success of Bryopsis has also been attributed to its associations with endophytic bacteria that reside in the cytoplasm of their cells.
Dictyochloris is a genus of green algae in the class Chlorophyceae. It is the sole genus of the family Dictyochloridaceae. It is commonly found in terrestrial and subaerial habitats.
Dictyochloropsis is a genus of unicellular green alga of the phylum Chlorophyta. This genus consists of free-living algae which have a reticulate (net-like) chloroplast that varies slightly in morphology between species, and that when mature always lacks a pyrenoid. Dictyochloropsis is asexual and reproduces using autospores.
Dictyosphaerium is a genus of green algae, in the family Chlorellaceae. It occurs in freshwater habitats around the world and is planktonic.
Trebouxia is a unicellular green alga. It is a photosynthetic organism that can exist in almost all habitats found in polar, tropical, and temperate regions. It can either exist in a symbiotic relationship with fungi in the form of lichen or it can survive independently as a free-living organism alone or in colonies. Trebouxia is the most common photobiont in extant lichens. It is a primary producer of marine, freshwater and terrestrial ecosystems. It uses carotenoids and chlorophyll a and b to harvest energy from the sun and provide nutrients to various animals and insects.
Coccomyxa is a genus of green algae in the family Coccomyxaceae. This genus is defined by their small, elliptical to spherical shape, and the presence of a simple parietal chloroplast. These features, along with their occurrence in various lifestyles such as free-living, parasitic, or as photobionts, have been used to identify more than 40 species. Using additional morphological features, such as brown akinetes formation, allows for the differentiation between Coccomyxa and the genus Pseudococcomyxa, as they tend to share some morphological characteristics like the general cell shape and one-sided mucilage cap. Recent molecular analysis, however, indicates that the genus Pseudococcomyxa is contained within different Coccomyxa clades, signaling the fact that the two genera are the same. Coccomyxa has often been used as a model organism, and its genome is being completely sequenced. The genus is also an attractive candidate for biofuels.
Algaemia is a secondary term that refers to the emerging condition in which green algae enter the bloodstream. Members of the genus Prototheca are the most common algae that leads to algaemia. Prototheca and Chlorella, which is extremely rare, are the only two known algae genera capable of inflicting disease on mammals, including humans, through invasion of host tissue. The majority of cases are observed in dairy cattle as a cause of bovine mastitis as well as other domesticated animals. Cases of algaemia have been observed in dogs and cats as well. Few cases have been observed in humans. Human cases of algaemia or, protothecosis, are examined on a case-by-case basis due to the particularity of each case. Protothecosis infection is classified based on the symptoms: (i) cutaneous lesions, (ii) olecranon bursitis, and (iii) disseminated or systemic type infections.
Phacus is a genus of unicellular excavates, of the phylum Euglenozoa, characterized by its flat, leaf-shaped structure, and rigid cytoskeleton known as a pellicle. These eukaryotes are mostly green in colour, and have a single flagellum that extends the length of their body. They are morphologically very flat, rigid, leaf-shaped, and contain many small discoid chloroplasts.
Lichen anatomy and physiology is very different from the anatomy and physiology of the fungus and/or algae and/or cyanobacteria that make up the lichen when growing apart from the lichen, either naturally, or in culture. The fungal partner is called the mycobiont. The photosynthetic partner, algae or cyanobacteria, is called the photobiont. The body of a lichens that does not contain reproductive parts of the fungus is called the thallus. The thallus is different from those of either the fungus or alga growing separately. The fungus surrounds the algal cells, often enclosing them within complex fungal tissues unique to lichen associations. In many species the fungus penetrates the algal cell wall, forming penetration pegs or haustoria similar to those produced by pathogenic fungi. Lichens are capable of surviving extremely low levels of water content (poikilohydric). However, the re-configuration of membranes following a period of dehydration requires several minutes at least.
Symbiosis in lichens is the mutually beneficial symbiotic relationship of green algae and/or blue-green algae (cyanobacteria) living among filaments of a fungus, forming lichen.
Prototheca zopfii is an ubiquitous achlorophyllic green alga. It is a known cause of mastitis in cattle.
Chlorellosis is a disease caused by the infection of Chlorella, a type of microalgae containing large amount of chloroplasts. It is mainly found in sheep and cattle, while cases in humans, dogs, antelopes, beavers, camels and fish, were also reported. Symptoms of Chlorellosis including focal cutaneous lesions, lymphadenitis, and peritonitis.
Asterochloris is a genus of green algae in the family Trebouxiophyceae. It is a common photobiont in lichen, occurring in the thalli of more than 20 lichen genera worldwide. Asterochloris is distinguishable from the morphologically similar genus Trebouxia, primarily due to its deeply lobed chloroplast, the placement of the chloroplast along the cell's periphery before the initiation of zoospore or aplanospore formation, and its tendency to primarily reproduce asexually through the production of aplanospores.
Citing public domain text from the CDC.
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