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A protist (/ ˈ p r oʊ t ɪ s t /) is any eukaryotic organism (one with cells containing a nucleus) that is not an animal, plant, or fungus.The protists do not form a natural group, or clade, since they exclude certain eukaryotes with whom they share a common ancestor; [a] but, like algae or invertebrates, the grouping is used for convenience.
The taxon 'Protozoa' fails to meet these standards, so grouping protozoa with animals, and treating them as closely related, became no longer justifiable. The term continues to be used in a loose way to describe single-celled protists (that is, eukaryotes that are not animals, plants , or fungi ) that feed by heterotrophy . [ 9 ]
Actinophrys species belong to an informal group known as heliozoa, which are unicellular eukaryotes (or protists) that are heterotrophic (also known as protozoa) and present stiff radiating arms known as axopodia. [3] [4] In particular, Actinophrys species are characterized by axonemes consisting of double interlocking spirals of microtubules.
Protozoan infections are parasitic diseases caused by organisms formerly classified in the kingdom Protozoa. These organisms are now classified in the supergroups Excavata, Amoebozoa, Harosa (SAR supergroup), and Archaeplastida. They are usually contracted by either an insect vector or by contact with an infected substance or surface. [1]
The name DRIP is an acronym for the first protozoa identified as members of the group, [5] Cavalier-Smith later treated them as the class Ichthyosporea, since they were all parasites of fish. order Dermocystida "D": Dermocystidium. One species, Rhinosporidium seeberi, infects birds and mammals, including humans.
Its field of study therefore overlaps with the more traditional disciplines of phycology, mycology, and protozoology, just as protists embrace mostly unicellular organisms described as algae, some organisms regarded previously as primitive fungi, and protozoa ("animal" motile protists lacking chloroplasts).
Virulence factors (preferably known as pathogenicity factors or effectors in botany) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following: [1] [2] colonization of a niche in the host (this includes movement towards and attachment to host cells ...
Since the decade of the 2000s, the eukaryotic tree of life (abbreviated as eToL) has been divided into 5–8 major groupings called 'supergroups'. These groupings were established after the idea that only monophyletic groups should be accepted as ranks, as an alternative to the use of paraphyletic kingdom Protista. [2]