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glossary
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| GASTROTRICH
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A type of metazoan, resembling some ciliates. [Link to this definition]
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| GELATINOUS
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With a jelly-like consistency [Link to this definition]
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| GENERA
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Plural of genus. [Link to this definition]
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| GENUS
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A taxonomic rank above the level of species (there are one or more species in a genus). Organisms carry two names (e.g. Pompholyxophrys punicea or Paramecium aurelia), usually written in italics. The second name is the species name, the first is the name of the genus. It may be abbreviated to a single letter where the meaning is unambiguous (P. aurelia or H. sapiens). Strictly, all genera have different names, but occasionally the same name is used twice (for example for a plant and for an animal). [Link to this definition]
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| GIF
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A format for digital images, widely used for drawings and other schematics because GIF images require little memory and can be quickly communicated for display. In preparing digital images for this site, all early editing should be done using the TIF format to preserve quality. However, final images should be saved in jpg format if photographs, or GIF if drawings. Both types of image require less memory, but there is a degradation in quality. This is illustrated in the picture. A pair of parallel lines with a colour gradient were drawn, saved using the different file formats, and then magnifed 10 times. The tif images show slight loss of sharpness but retain the tonal range and colour quality; gif images retain sharpness but the tonal range is converted into a series of steps; and the jpg showstonal range but considerable degradation of colour quality. [Link to this definition]
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| GLIDE
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A form of movement in which the organism remains in contact with the substrate. The movement is gradual and the contribution made by individual organelles of locomotion is not evident (compare with crawling). Found in cyanobacteria (illustrated) diatoms and many flagella [Link to this definition]
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| Glycocalyx
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An organic coat, covering, sheath or extracellular matrix extending from the outer surface of the plasma membrane ; e.g., the organic layer coating the surface membrane of many “naked” rhizopod amoebae, the mucilaginous cell coat covering the plasma membrane in some “naked” algal protists (e.g., the green alga Dunaliella), the cell coat on zoospores of some oomycetes (e.g., Phytophthora, Lagenidiuni) and chytridiomycetes (e.g., Polyphagus, Chytriomyces), or the surface covering of other protists ranging from trypanosomes to ciliates. The surface coat, among other surface membrane components, confers antigenic cellular specificity. Variations among “naked” amoebae include surface coats that: (1) are amorphous and thin or thick, (2) consist of various configurations that are not resolvable into separate structures (fuzzy, with a suggestion of an organized pattern, or containing hexagonal or tubular elements), or (3) contain more discrete structures, varying in geometry, arranged in a definite pattern, and not separable intact from the surface membrane (see Glycostyle). [Link to this definition]
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| Glycostyle
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Complex, flexible, discrete structures attached to the surface of cells (especially “naked” amoebae), each separate from its neighbors, arranged in a definite pattern, and not removable intact from the cell surface. In “naked” amoebae, the glycostyles vary among genera (e.g., pentagonally symmetrical in Vannella, and hexagonal in Vexilliferd). Glycostyles are distinguished from other discrete surface structures such as scales, plates, and spicules , by being flexible, sometimes erect, projections from the cell surface. [Link to this definition]
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| GOLDEN
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A colour usually used in reference to chloroplasts containing chlorophylls a and c, as of chrysomonads. Other colours are green or blue-green. [Link to this definition]
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| GRANULES
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Solid inclusions in cells or items adhering to the surface of cells. Usually refractile, in that they may look bright when viewed with the microscope. [Link to this definition]
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| GRANULORETICULOSE
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Referring to a type of pseudopodia usually found in the marine foraminifera. The pseudopodia have a granular texture and form a network (see Lieberkuehnia Fig. **). Hence granuloreticulose amoebae. [Link to this definition]
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| GRATICULE
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A glass disc with an scale, grid or other pattern etched into the surface. Placed in the eyepiece of a microscope, calibrated against a scale on a slide and used (mostly) to measure the sizes of microscopic objects. [Link to this definition]
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| GREEN
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A term used in reference to the colour of chloroplasts and indicating that chlorophyll B is present. Plastids without chlorophyll B are less bright in colour, and may be off-green, golden, or blue-green. Chlorophyll B containing chloroplasts are found in euglenids, green algae (including volvocids) and some symbiotic algae of ciliates and amoebae. [Link to this definition]
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| GROMIIDA
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Used to refer to amoebae with filose pseudopodia and a lorica. [Link to this definition]
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| GROOVE
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A long shallow depression on a surface [Link to this definition]
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| GULLET
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A term that is sometimes used to refer to a depression on a cell surface, particularly one into which flagella are inserted (see flagellar pocket). Not a desirable term as it misleadingly suggests a role in food uptake. [Link to this definition]
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| Gun cell
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Developing from an encysting zoospore of the oomycete Haptoglossa, this apparatus consists of a cell with: (1) an extracellular plug and projectile located in an invaginated chamber of the cell surface and (2) an intracellular complex system of vacuoles. These components are used to forcibly discharge the missile-shaped projectile into rotifer or nematode hosts which collide with the cell, injecting infective sporidia through the host cuticle and into the host body where the fungal-protist grows into cylindrical thalli. This mechanism of host infection is similar to one found among some members of the plasmodiophoromycetes infecting plants (see Stachel), but differs in its explosive trigger and discharge of the structure used to pierce the host surface. The discharge vesicle of the Microsporidia can be considered a type of gun cell. [Link to this definition]
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