|
Trebouxiophyceae
The Trebouxiophyceae, also known as trebouxiophytes, are a class of green algae, in the division Chlorophyta. Members of this class are single-celled, colonial, or multicellular and are found in freshwater, terrestrial or marine habitats worldwide. Many taxa in the Trebouxiophyceae form symbiotic relationships with other organisms; in particular, the majority of phycobionts within lichens are trebouxiophytes. A number of taxa have also lost the ability to photosynthesize, and have evolved to become parasitic; examples include '' Prototheca'' and '' Helicosporidium''. Trebouxiophyceae was originally defined by ultrastructural characteristics, but is now generally circumscribed based on phylogenetics, particularly based on the 18S rDNA locus. As of 2024, Trebouxiophyceae contains 211 genera and about 925 species. Morphology Members of the Trebouxiophyceae are microscopic or macroscopic organisms which exist in a variety of forms: non-flagellate coccoid or elliptical single cells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyta
Chlorophyta is a division of green algae informally called chlorophytes. Description Chlorophytes are eukaryotic organisms composed of cells with a variety of coverings or walls, and usually a single green chloroplast in each cell. They are structurally diverse: most groups of chlorophytes are unicellular, such as the earliest-diverging prasinophytes, but in two major classes ( Chlorophyceae and Ulvophyceae) there is an evolutionary trend toward various types of complex colonies and even multicellularity. Chloroplasts Chlorophyte cells contain green chloroplasts surrounded by a double-membrane envelope. These contain chlorophylls '' a'' and '' b'', and the carotenoids carotin, lutein, zeaxanthin, antheraxanthin, violaxanthin, and neoxanthin, which are also present in the leaves of land plants. Some special carotenoids are present in certain groups, or are synthesized under specific environmental factors, such as siphonaxanthin, prasinoxanthin, echinenone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Green Algae
The green algae (: green alga) 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 within the charophytes 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prasiola
''Prasiola'' is a genus of macroscopic green algae, found in a variety of habitats ranging from terrestrial, freshwater, to marine. The genus has a cosmopolitan distribution, ranging from the Arctic to the Antarctic. Plants belonging to the genus ''Prasiola'' were first described by John Lightfoot in 1777 in his series ''Flora Scotica'', as the name ''Ulva crispa''. In 1838, Giuseppe Giovanni Antonio Meneghini circumscribed the genus. Species of ''Prasiola'' are edible and are often harvested for food, particularly '' Prasiola japonica'', in countries such as Japan and Myanmar. Description ''Prasiola'' forms single-layered blades which may range in shape from fan-shaped, ribbon-shaped, to wedge-shaped and may or may not have a distinct stipe. In some species, plants start as uniseriate, unbranched filaments or thin ribbons. Blades may be attached to a substrate or may be freely floating or lying. Individual cells are quadrangular, and arranged in regular rows, sometimes gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prototheca
''Prototheca'' is a genus of algae in the family Chlorellaceae. 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. Etymology 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. Biology ''Prototheca'' consists of microscopic, single cells, which may sometimes be clustered to form irre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lichens
A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), mutualistic relationship.Introduction to Lichens – An Alliance between Kingdoms . University of California Museum of Paleontology. . Lichens are the lifeform that first brought the term symbiosis (as ''Symbiotismus'') into biological context. Lichens have since been recognized as important actors in nutrient cycling and producers which many higher trophic feeders feed on, such as reindeer, gastropods, nematodes, mites, and springtails. Lichens have properties different from those of their component organisms. They come in man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eremosphaera
''Eremosphaera'' is a genus of green algae in the family Oocystaceae. It was first described by Heinrich Anton de Bary in 1858, who thought it was a desmid. Since then, many authors have debated its classification, until its modern placement in the family Oocystaceae. ''Eremosphaera'' is widely distributed in freshwater habitats around the world. Most species of ''Eremosphaera'', including the type species ''E. viridis'' are associated with ''Sphagnum'' bogs, which are characteristically acidic and associated with desmids. A few species prefer alkaline habitats, such as '' Eremosphaera minor'' which grows in alkaline soil. Because of its large size, it is used as a model organism to study cell physiology. The genus name comes from the Greek roots ''eremos'', meaning "solitary", and ''sphaira'', meaning "ball". Description ''Eremosphaera'' consists of relatively large cells which are solitary or in clusters of two to four, with or without a mucilaginous envelope. Cells are spher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicosporidium
''Helicosporidium'' is a genus of colorless, pathogenic algae in the class Trebouxiophyceae of the green algae. It is a parasite found in the gut of insects, and a close relative of '' Prototheca''. History of knowledge The genus ''Helicosporidium'' was first described in England by David Keilin in 1921. He isolated the parasite from the ceratopogonid fly '' Dasyhelea obscura'', and named the species ''Helicosporidium parasiticum''. In 1931, the genus and species names were validated, it was placed in its own order Helicosporidia. In 1970, ''Helicosporidium'' was discovered from Argentina infecting a lepidopteran. ''Helicosporidium'' infections, although rare, have been discovered around the world and in a diverse range of host organisms. The unique morphology of ''Helicosporidium'' has made it easy to identify, but difficult to classify. ''Helicosporidium'' has at various points been considered to be a protozoan or an ascomycete fungus. It was not until molecular phylogenetics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prasinophyte
The prasinophytes are a group of unicellular green algae. Prasinophytes mainly include marine planktonic species, as well as some freshwater representatives.Sym, S. D. and Pienaar, R. N. 1993. The class Prasinophyceae. In Round, F. E. and Chapman, D. J. (eds) ''Progress in Phycological Research'', Vol. 9. Biopress Ltd., Bristol, pp. 281-376. The prasinophytes are morphologically diverse, including flagellates with one to eight flagella and non-motile (coccoid) unicells, as well as dormant or cyst stage phycoma. The cells of many species are covered with organic body scales; others are naked. Well studied genera include '' Ostreococcus'', considered to be the smallest (ca. 0.95 μm) free-living eukaryote, and '' Micromonas'', both of which are found in marine waters worldwide. Prasinophytes have simple cellular structures, containing a single chloroplast and a single mitochondrion. The genomes are relatively small compared to other eukaryotes (about 12 Mbp for '' Ostreococcus'' an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which capture the Radiant energy, 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. Chloroplasts are highly dynamic—they circulate and are moved around within cells. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts cannot be made anew by the plant cell and must ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autospore
Autospores are a type of spores that are produced by algae to enable asexual reproduction and spread. They are non-motile and non-Flagellated cell, flagellated Aplanospore, aplanospores that are generated within a parent cell and have the same shape as the parent cell before their release. Autospores are also known as resting spores. Algae primarily use three different types of spores for asexual reproduction - autospores, Zoospore, zoospores, and aplanospores. Autospores occur in several groups of algae, including ''Eustigmatophyceae'', ''Dinoflagellate, Dinoflagellates'', and green algae. One example of a colonial alga that produces autospores is Dichotomococcus. This alga generates two autospores per reproducing cell, and the autospores escape through a slit in the cell wall and remain attached to the mother cell. Some study on autospores and algae in general include looking into its use for biofuel, animal feed, food supplements, nutraceuticals, and pharmaceuticals. Autospore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitic
Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson characterised parasites' way of feeding as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes. There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), trophicallytransmitted parasitism (by being eaten), vector-transmitted parasitism, parasitoidism, and micropredation. One major axis of classification concerns invasiveness: an endopar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisogamy
Different forms of anisogamy: A) anisogamy of motile cells, B) 283x283px Anisogamy is a form of sexual reproduction">egg cell">oogamy (egg cell and sperm cell), C) anisogamy of non-motile cells (egg cell and spermatia).">283x283px Anisogamy is a form of sexual reproduction that involves the union or fusion of two gametes that differ in size and/or form. The smaller gamete is male, a ''microgamete'' or sperm cell, whereas the larger gamete is female, a larger ''macrogamete'' or typically an egg cell. Anisogamy is predominant among multicellular organisms. In both plants and animals, gamete size difference is the fundamental difference between females and males. Anisogamy most likely evolved from isogamy. Since the biological definition of male and female is based on gamete size, the evolution of anisogamy is viewed as the evolutionary origin of male and female sexes. Anisogamy is an outcome of both natural selection and sexual selection, and led the sexes to different prima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
