|
Neometanemidae
''Neometanema'' is a genus of phagotrophic flagellates belonging to the Euglenida, a diverse group of flagellates in the phylum Euglenozoa. It is the sole genus within the monotypic family Neometanemidae and suborder Metanemina. It composes the order Natomonadida together with a closely related clade of osmotrophs known as Aphagea. Description ''Neometanema'' is a genus of unicellular flagellates, microscopic eukaryotes or protists that swim by using two flagella that are equally long. The cells are flattened in shape, with a visible feeding apparatus. It is a euglenid, characterized by the presence of pellicle strips below the cell surface; in particular, ''Neometanema'' species have 22 pellicle strips arranged helically through the cell. Like other euglenids of the Spirocuta clade, ''Neometanema'' cells are capable of metaboly (flexible peristaltic movement), although more weakly than others. They are distinguished by the closely related genera ''Heteronema'' and ''Anison ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglenozoa
Euglenozoa are a large group of flagellate Discoba. They include a variety of common free-living species, as well as a few important parasites, some of which infect humans. Euglenozoa are represented by four major groups, ''i.e.,'' Kinetoplastea, Diplonemea, Euglenida, and Symbiontida. Euglenozoa are unicellular, mostly around in size, although some euglenids get up to long. Structure Most euglenozoa have two flagella, which are inserted parallel to one another in an apical or subapical pocket. In some these are associated with a cytostome or mouth, used to ingest bacteria or other small organisms. This is supported by one of three sets of microtubules that arise from the flagellar bases; the other two support the dorsal and ventral surfaces of the cell. Some other euglenozoa feed through absorption, and many euglenids possess chloroplasts, the only eukaryotes outside Diaphoretickes to do so without performing kleptoplasty, and so obtain energy through photosynthesis. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglenid
Euglenids or euglenoids are one of the best-known groups of eukaryotic flagellates: single-celled organisms with flagella, or whip-like tails. They are classified in the phylum Euglenophyta, class Euglenida or Euglenoidea. Euglenids are commonly found in fresh water, especially when it is rich in organic materials, but they have a few marine and endosymbiotic members. Many euglenids feed by phagocytosis, or strictly by diffusion. A monophyletic subgroup known as Euglenophyceae have chloroplasts and produce their own food through photosynthesis. This group contains the carbohydrate paramylon. Euglenids split from other Euglenozoa (a larger group of flagellates) more than a billion years ago. The plastids (membranous organelles) in all extant photosynthetic species result from secondary endosymbiosis between a euglenid and a green alga. Structure Euglenoids are distinguished mainly by the presence of a type of cell covering called a pellicle. Within its taxon, the pellic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microscopic
The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as the scale between the macroscopic scale and the quantum scale. Microscopic units and measurements are used to classify and describe very small objects. One common microscopic length scale unit is the micrometre (also called a ''micron'') (symbol: μm), which is one millionth of a metre. History Whilst compound microscopes were first developed in the 1590s, the significance of the microscopic scale was only truly established in the 1600s when Marcello Malphigi and Antonie van Leeuwenhoek microscopically observed frog lungs and microorganisms. As microbiology was established, the significance of making scientific observations at a microscopic level increased. Published in 1665, Robert Hooke's book Micrographia details his microscopic observations inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisonema
''Anisonema'' is a genus of colorless flagellates that occur in marine, brackish, and freshwater habitats. The cell is typically ovoid, somewhat flattened, and rigid. The name ''Anisonema'' derives from Greek for "unequal thread", in reference to the two flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ... that are of unequal lengths. The shorter flagellum extends forwards and propels movement with a sweeping motion, while the longer flagellum, up to three times the length of the cell, trails behind, with jerking contractions. The genus was first named by French biologist Félix Dujardin his 1841 ''Histoire naturelle des zoophytes. Infusoires, comprenant la physiologie et la classification de ces animaux, et la manière de les étudier à l'aide du microscope''. , there a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heteronema
''Heteronema'' is a genus of phagotrophic, flagellated euglenoids that are most widely distributed in fresh water environments.Guiry, M. D.; Guiry, G. M. (2012). “Heteronema Dujardin, 1841”. Retrieved February 14, 2019, fro/ref> This genus consists of two very distinguishable morphogroups that are phylogenetically closely related.Lax, G.; Simpson, A. G. (2013). “Combining Molecular Data with Classical Morphology for Uncultured Phagotrophic Euglenids (Excavata): A Single-Cell Approach". Journal of Eukaryotic Microbiology. 6: 615-625doi: 10.1111/jeu.12068/ref>Lee, Won J. (2011). “Free-living benthic heterotrophic euglenids from Botany Bay, Australia”. Marine Biology Research. 8 (1): 3-27doi: 10.1080/17451000.2011.596545/ref> These morphogroups are deciphered based on shape, locomotion, and other ultrastructural traits. However, this genus does pose taxonomic problems due to the varying historical descriptions of ''Heteronema'' species and their similarity to the genus ''Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaboly
Spirocuta () is a clade of euglenids, single-celled eukaryotes or protists belonging to the phylum Euglenozoa. They are distinguished from other euglenids by active deformation of their cell shape, a process called euglenid motion or metaboly. This is made possible by a high number of spirally arranged protein strips that run below their cell membrane and confer the cell with flexibility. These strips compose the helicoidal pellicle (biology), pellicle, a trait referenced by the alternative name Helicales. Description Spirocuta is a group of flagellates, unicellular eukaryotes or protists with one or two flagella for locomotion in the anterior region of the cell. The move through a gliding motility, gliding motion in contact with the substrate to propel the cell forward. Like other members of the Euglenida, their cells are lined by a pellicle (biology), pellicle composed of proteinaceous strips that interlock with each other, and are spirally arranged underneath the cell membran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Surface
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of a cell, being selectively permeable to ions and organic molecules ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pellicle (biology)
Protozoa (: protozoan or protozoon; alternative plural: protozoans) are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically, protozoans were regarded as "one-celled animals". When first introduced by Georg Goldfuss, in 1818, the taxon Protozoa was erected as a class within the Animalia, with the word 'protozoa' meaning "first animals", because they often possess animal-like behaviours, such as motility and predation, and lack a cell wall, as found in plants and many algae. This classification remained widespread in the 19th and early 20th century, and even became elevated to a variety of higher ranks, including phylum, subkingdom, kingdom, and then sometimes included within the paraphyletic Protoctista or Protista. By the 1970s, it became usual to require that all taxa be monophyletic (derived from a common ancestor that would also be regarded as protozo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagella
A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many protists with flagella are known as flagellates. A microorganism may have from one to many flagella. A gram-negative bacterium '' Helicobacter pylori'', for example, uses its flagella to propel itself through the stomach to reach the mucous lining where it may colonise the epithelium and potentially cause gastritis, and ulcers – a risk factor for stomach cancer. In some swarming bacteria, the flagellum can also function as a sensory organelle, being sensitive to wetness outside the cell. Across the three domains of Bacteria, Archaea, and Eukaryota, the flagellum has a different structure, protein composition, and mechanism of propulsion but shares the same function of providing motility. The Latin word means " whip" to describe its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protist
A protist ( ) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus. Protists do not form a natural group, or clade, but are a paraphyletic grouping of all descendants of the last eukaryotic common ancestor excluding land plants, animals, and fungi. Protists were historically regarded as a separate taxonomic kingdom known as Protista or Protoctista. With the advent of phylogenetic analysis and electron microscopy studies, the use of Protista as a formal taxon was gradually abandoned. In modern classifications, protists are spread across several eukaryotic clades called supergroups, such as Archaeplastida ( photoautotrophs that includes land plants), SAR, Obazoa (which includes fungi and animals), Amoebozoa and " Excavata". Protists represent an extremely large genetic and ecological diversity in all environments, including extreme habitats. Their diversity, larger than for all other eukaryotes, has only been discovered in rece ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
