Euglenozoa

Euglenozoa

Scientific Classification
Kingdom: Protista Phylum: Euglenozoa
Typical Classes
Euglenoidea Kinetoplastea Diplonemea Postgaardea

Euglenozoa are part of a large group of flagellate protozoans, that sometimes infect human beings causing disease. Most of the species are free-living including some parasites. Under the Phylum Euglenozoa, are two main subgroups which are the euglenids and kinetoplastids.[1] Through a series of tests on genetics of this particular organism, the organisms name's suffix, ("zoa" meaning animal), has proven to be incorrect, and that members of Euglenozoa are not plant or animal.

Anatomy

Euglenozoa in general have two flagella that are placed parallel to each other in an apical or subapical space. A Euglenozoa has a mouth called a cytostome, which is used to ingest bacteria and small organisms.[2]The cells anatomy changes only slightly between the two main groups of Euglenozoons, euglenids and kinetoplastids. Both types of cells, as expected have unique characteristics that separate themselves from other cells of other organisms. An example of these unique characteristics is that kinetoplastids have a a group or “clump” that has or contains DNA at one end of the mitochondrion. This “clump” is also known as the kinetoplast. The “pellicle”, is when the euglenids' cell surface. The “pellicle” is flexible, and makes it so cells are able to move around. Mitochondria, of all Euglenozoons, have discoid cristae. Cristae are disk-shaped folds within the mitochondria which provide more surface area for cell respiration. The cytoskeleton of the Euglenozoans have a regular layout of cortical microtubules, a unique acentrosomal showing that is essential for plant morphogenesis. Chloroplasts, as said above, are used for photosynthesis, have chlorophylls a and b. They also have envelopes of three membranes. The plastids located in the cytosol, and do not have any starch content. Euglenozoa contains both autotrophs and heterotrophs, which means that some are able to provide food for themselves (autotrophes), and some rely on other organisms for their nourishment (heterotrophes). The euglenids with chloroplasts are able to use photosynthesis for the nourishment and energy that is needed, while the rest feed on bacteria.[3]

Reproduction

Reproduction takes place only through cell division. When mitosis takes place, the nuclear membrane stays intact or in place, and the spindle microtubules forms inside of it which carries on the reproduction.[4]Euglenoids reproduce very quickly and create many offspring. They absorb their flagellum and divide haploid cells by using mitosis. Mitosis produces 4-8 flagellated haploid cells, called zoospores. The zoospores then break out of the adult and grow to be full size adults, and carry on the same reproductive patterns as their "parents".

Ecology

Euglenozoons usually live in freshwater streams and ponds, as well as marine environments. Some may live in vertebrates bloodstreams which serve as hosts. Euglenoids possess cytoplasts. Euglenoids are usually found in shallow areas, and usually need warm, sunny water. They need this in order to maximize their life span and living conditions. The other animals that inhabit the water, alongside Euglenoids, give them the nutrients and nourishment that is needed for proper conditions. Although most of the Euglenoids live in freshwater, some smaller species have been known to inhabit mud, swamps, and in or on the sand.[5]Euglenozoa feed through absorption. Most Eugelnids collect energy using chloroplasts to obtain photosynthesis. The chloroplasts that are used are surrounded by three membranes that have chlorophyll, as well as a few other pigments.[6]

Life Cycle

There is a very large range of life cycles in euglenozoans which is determined by their grouping. A kinetoplastid member of Euglenozoa is transmitted or moved as well as reproduced while in a host, by a vector. The most common host for such parasites is the tsetse fly. The fly then takes on the the parasite and allows it to reproduce. There are still many tests being taken to specify how the parasite moves through the fly’s digestions system. At this time, it morphs into a metacyclic trimastigote form, where mitochondria minimizes some of the cristae and then is free to move around in the salivary gland. This is where it waits for the host(tsetse fly) to feed again so that it can be delivered to the next host. Euglenoids lifestyles are extremely similar to that of green algae mostly because they both have a green pigment. Euglenids have the same reproductive scheme with their kinetoplastid. They are similar because they both use cell division for reproduction. [7]