| MACRONUCLEUS
|
One of two types of nuclei found in ciliates. Typically the larger of the two, may be rounded, like a long sausage, or like a string of beads. Involved in production of proteins but not in sexual reproduction. Essential for the day to day activities of the ciliate (see micronucleus). In this apostome ciliate, the macronucleus is the long rod shaped structure to the lower half of the image, and the small ovoid structure attached to the top of the nucleus is the micronucleus. [Link to this definition]
|
| MAGNIFICATION
|
Aa measure of the enlargement of an image relative to an object. Normally, it is simpler and more informative to refer to the real size of the object. [Link to this definition]
|
| MARGINAL ROW
|
Relating to cirri of hypotrichs specifying the one or two rows nearest to the lateral margin of the cell. May be continuous around the posterior end of the cell (one row) or broken at the posterior end (two rows). [Link to this definition]
|
| MASTAX
|
Part of the digestive system of rotifers, a grinding structure lying just behind the mouth. [Link to this definition]
|
| MASTIGAMOEBAE
|
A kind of flagellate with a single flagellum and a cell body which produces pseudopodia, usually from anoxic sites (e.g., Mastigamoeba) [Link to this definition]
|
| MATRIX
|
Relating to the structure or consistency of material. [Link to this definition]
|
| MEASURING EYEPIECE
|
A type of eyepiece for a microscope which includes an etched scale. After calibration against a micrometer slide, this may be used to measure the size of microscopic objects. [Link to this definition]
|
| MEDIAN
|
Near the centre (as of cell, e.g. median nucleus). [Link to this definition]
|
| MEDIAN
|
Near the centre (as of cell, e.g. median nucleus). [Link to this definition]
|
| MEDIUM
|
The fluid environment in which protists live or the solution of salts and other materials in which they are cultured. Also a relative size of organism, which depends on the group under consideration. Medium sized flagellates are 10 to 30 microns, medium sized amoebae and ciliates 40 to 100 microns. [Link to this definition]
|
| MEMBRANELLE
|
A compound structure comprised of many cilia and associated with the mouth of a ciliate. Either present in groups of three (Oligohymenophora) or as a band of many more (Polyhymenophora). [Link to this definition]
|
| METABOLY
|
Change. Either used in reference to change in molecules (metabolism) or change in cell shape, as in euglenoid motion. [Link to this definition]
|
| METAL SALTS
|
Soluble or insoluble chemical compounds which incorporate one or more metal ions (such as iron, manganese, calcium or sodium) [Link to this definition]
|
| METAZOA
|
Animals (singular metzoon, adjective, metazoan). [Link to this definition]
|
| MICROGRAPH
|
A photograph taken using a microscope. [Link to this definition]
|
| MICROMETER SLIDE
|
A glass slide with a scale (usually 1 mm.) etched on its surface. Used to calibrate the field of view or the scale in a measuring eyepiece, such that sizes of objects viewed with a microscope can be measured. [Link to this definition]
|
| MICROMETRE
|
A unit of length, one millionth of a metre, written æm. [Link to this definition]
|
| MICRON
|
A micrometre - one thousandth of the millimetre, usually abbreviated as the greek letter or greek letter with an m after it. [Link to this definition]
|
| MICRONUCLEUS
|
One of two kinds of nuclei found in ciliates, dividing to produce two similar nuclei during asexual reproduction and producing nuclei with half the complement of DNA for sexual activity. Usuaully the smaller of the two types of nuclei, but many may be present. Some cells lack a micronucleus and survive quite well without it. [Link to this definition]
|
| MICROSCOPE
|
In the context of this book, a device with glass or plastic lenses the function of which is to produce a magnified image of an object. Of two common types, compound and dissecting. In a broader context, these are kinds of light microscope, but microscopes producing images from sound, beams of electrons etc. are also available. [Link to this definition]
|
| Microtubular roots
|
Flagellar roots consisting of one or more microtubules originating at or near a basal body/kinetosome; the microtubules having a greater stability when compared to cytoplasmic microtubules. A-tubulin of microtubular roots is acetylated in at least some protists, and this posttranslational modification may characterize all microtubular roots. Acetylated a-tubulin stabilizes microtubules so that they fail to disassemble at low temperatures or high pressure. Microtubular roots vary in number, with one or two roots per basal body/kinetosome being common. The paths of microtubular roots are usually superficial (near the plasma membrane), and their relative directions and curvatures are of primary importance in determining the morphology of a cell. The number of microtubules per root varies from one to over 80. When more than one microtubule is present in a root, the microtubules often run parallel for considerable distances and are associated laterally via intermicrotubular linkers. Microtubular roots arise from microtubular organizing centers (MTOCs) along or near the basal bodies/kinetosomes. At this time little is known about these MTOCs. Microtubular roots change as flagella/cilia transform from immature to mature forms, but it is unknown if the MTOCs change during maturation or if there are separate MTOCs for immature and mature flagellar/ciliary roots. Some microtubular roots contain MTOCs along their surfaces, and they in turn can give rise to cytoplasmic microtubules. These cytoplasmic microtubules are usually disassembled by cold or high pressure, suggesting they are not acetylated. However, some are stable in cold or high pressure. These cytoplasmic microtubules are usually involved in a vital cell function such as maintaining morphological contours for reproduction or feeding and forming or transporting scales or scale vesicles. Synonyms: microtubular rootlets. [Link to this definition]
|
| MICROTUBULE
|
A subcellular structure comprised of the protein tubulin and used for support - part of the cytoskeleton. Individual microtubules cannot be seen by conventional light-microscopy, but aggregates of microtubules can. [Link to this definition]
|
| MITOCHONDRIA
|
A component of some eukaryotic cells. An organelle surrounded by two membranes within which some of the pathways of aerobic respiration are carried out. This function increases the energy output from food by about a facfor of 10. Cells may have one to many mitochondria, and they may be spherical, sausage-like or branched. They were probably formed in evolutionary terms by an event of symbiosis in which a cell capable of aerobic respiration was acquired by another cell and the association became stable. The irregular threads in this diatom are mitochondria. [Link to this definition]
|
| Mixotrophic
|
Said of organisms capable of gaining energy and nutrients by both autotrophic and heterotrophic means. This is Paramecium bursaria, a ciliate with symbiotic algae, which means that it can carry out photsynthesis, but it also has a mouth and can ingest bacteria - attention is drawn to a food vacuole with an arrow. The terms amphitrophic and amphizoic are virtually interchangeable. [Link to this definition]
|
| MONOTHALAMID
|
Said of a type of amoeba with branching pseudopodia, in which the body is contained within a single chamber or shell. Usually regarded as members of the granuloreticulosea - that is related to the foraminifera. This is probably true for some monothalamids, but it is likely that not all organisms assigned to this group are closely related and therefore should not be classified together. [Link to this definition]
|
| MORPHOLOGY
|
The shape and form of an organism or part of an organism. [Link to this definition]
|
| MOTILE
|
Moving, for example by swimming, gliding, crawling, jumping, or kicking. Part of the body (e.g., cilia) may be motile in a cell which is not motile and is fixed in one position. [Link to this definition]
|
| MOUTH
|
Part of the body involved with the acquisition and internalization of food. The mouth usually includes a cytostome but may also involve elements external (such as a buccal cavity with buccal cilia) or internal (such as ingestion rods, extrusomes, cytopharynx) to the cytostome. This is Bursaria, and the mouth region includes a scoop-shaped cavity with lots of cilia curving into the cytostome located near the near left of the cell. [Link to this definition]
|
| MUCILAGINOUS
|
Made of, or with the texture of, mucus. [Link to this definition]
|
| Mucous pad
|
see
Adhesion pad.[Link to this definition]
|
| MYCELIA
|
The organization of the feeding stage of fungi, in which the cytoplasm is enclosed within a radiating system of walled tubes or hyphae. [Link to this definition]
|
