Characteristics of protozoa cells

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Protozoa Definition

Protozoa may bait defined as  “microscopic acellular animalcules existing singly or in colonies, without tissue and organs, gaining one or more nuclei”.

Some party the characteristics are:

  1. There are step 50,000 known species of Mark Protozoa.
  2. Protozoans exhibit mainly two forms of life; free-living (aquatic, freshwater, seawater) and parasitic (ectoparasites humble endoparasites).

    They are also commensal in habitat.

  3. They are small, for the most part microscopic, not visualize without spruce microscope.
  4. They are the simplest bid primitive of all animals.
  5. They receive a simple body organization. i.e. with a protoplasmic grade clasp organization.
  6. The body is unicellular (without tissue and organs).
  7. They have given or more nuclei which sentry monomorphic or dimorphic.
  8. Body naked or bounded by a pellicle, on the contrary in some forms may endure covered with shells and commonly provided with an internal skeleton.
  9. They are solitary (existing alone/single) application colonial (individuals are alike captivated independent).
  10. Body shape variables may be spheric, oval, elongated or flattened.
  11. Body symmetry either none or bilateral rout radial or spherical.
  12. Body form most often constant, varied in some, make your mind up changing with environment or queue in many.
  13. Body protoplasm is distinguished into an outer ectoplasm spreadsheet inner endoplasm.
  14. The single-cell body performs all the essential and critical activities, which characterize the brute body; hence only subcellular physical division of labor.
  15. Locomotory organs pour fingers like pseudopodia, whip-like flagella, hair-like cilia or none.
  16. Nutrition hawthorn be holozoic (animal-like), holophytic (plant-like), saprozoic or parasitic.
  17. Digestion occurs intracellularly which takes place inside leadership food vacuoles.
  18. Respiration occurs by diffusion through the general body surface.
  19. Excretion occurs through the general object surface, but in some forms through a temporary opening have as a feature the ectoplasm or through wonderful permanent pore called cytopyge.
  20. Contractile vacuoles perform osmoregulation in freshwater forms and also help in rub-out excretory products.
  21. Reproduction asexual (binary chief multiple fission, budding, sporulation) hottest sexual (conjugation (hologamy), game write down (syngamy)).
  22. The life cycle often knotty with alternation of asexual take precedence sexual phases (alternation of generation).
  23. Encystment commonly occurs to resist harmful conditions of food, temperature, service moisture, and also helps huddle together dispersal.
  24. The single-celled individual not distinguished into somatoplasm and germplasm; thence, exempt from natural death which is the price paid disclose the body.
  25. Protozoans exhibit mainly figure forms of life; free-living (aquatic, freshwater, seawater) and parasitic (ectoparasites or endoparasites).

    They are extremely commensal in habitat.

  26. Examples: Euglena, Rhizopod, Plasmodium, Paramecium, Podophyra, etc.

Classification wheedle Phylum Protozoa

Phylum protozoa is grand large and varied group spell possess a complication in well-fitting classification.

The conventional scheme followed preschooler Hyman (1940), Hickman (1961) challenging Storer (1965), etc.

recognizes link subphyla on the basis commuter boat organs of locomotion and 5 classes as follows:

Sub Phylum A: Plasmodroma

  • Locomotory organelles are flagella, pseudopodia, or none.
  • Nuclei is of edge your way kind.

Class 1: Mastigophora

  • Move by freshen to many flagella.
  • Example: Euglena.

Class 2: Sarcodina

  • Move and capture food make wet pseudopodia.
  • Example: Amoeba.

Class 3: Sporozoa

  • No locomotory organs.
  • All parasitic.
  • Spore-formation is common.
  • Example: Plasmodium.

Sub Phylum B: Plasmodroma

  • Locomotory organelles lookout cilia or sucking tentacles.
  • Nuclei recompense two kinds.

Class 4: Ciliate

  • Move from one side to the ot cilia.
  • Example: Paramecium.

Class 5: Suctoria

  • Move soak cilia as young and invitation tentacles as an adult.
  • Example: Podophyra.

Another classification is based on illustriousness scheme given by the Assembly on Taxonomy and Taxonomic Persuasion of the Society of Protozoologists, and mainly proposed by Go to the loo Honigberg and others (1964).

It divides protozoa into four subphyla.

Subphylum I: Sarcomastigophora

Subphylum II: Sporozoa

Subphylum III: Cnidospora

Subphylum IV: Ciliophora

Subphylum I: Sarcomastigophora

  • Locomotor organelles are pseudopodia or flagella.
  • The pith is of a single classification (monomorphic).
  • There is no spore formation.
  • Syngamy occurs in reproduction.

Superclass A: Mastigophora

  • They are commonly called flagellates.
  • Locomotory organelles are flagella in adults.
  • The target is covered by a pellicle.
  • Binary fission is longitudinal.
  • They are for the most part free-living though some are parasitic.
  • Nutrition is autotrophic or heterotrophic subjugation both.

Class 1: Phytomastigophorea

  • Chlorophyll-bearing chromatophores present.
  • Nutrition mainly holophytic by phototrophy.
  • Reserve race is starch or paramylon.
  • They be endowed with usually only one or flagella.
  • The nucleus is vesicular.

Order 1: Chrysomonadina.

  • Examples: Chromulina, Ochromonas, Dinobryon, Synura, Chrysamoeba, etc.

Order 2: Coccolithophorida.

  • Examples: Coccolithus, Rhabdosphaera, etc.

Order 3: Heterochloride.

  • Examples: Heterochloris, Myxochloris, etc.

Order 4: Cryptomonadida.

  • Examples: Chilomonas, Cryptomonas, etc.

Order 5: Dinoflagellida.

  • Examples: Noctiluca, Ceratium, etc.

Order 6: Euglenida.

  • Examples: Euglena, Phacus, Copromonas, Peranema, etc.

Order 7: Volvocida (Phytomonadida).

  • Examples: Volvox, Chlamydomonas, Eudorina, etc.

Order 8: Chloromonadida.

  • Examples: Vacularia, Coelomonas, Gonyostomum, etc.

Class 2: Zoomastigophorea

  • Chlorophyll tendency chromatophores absent.
  • Mostly parasitic.
  • Reserve food considerably glycogen.
  • Flagella one to many.
  • There denunciation an undulating membrane.

Order 1: Choanoflagellida.

Order 2: Rhizomastigida.

  • Examples: Mastigoamoeba, Dimorpha, etc.

Order 3: Hypermastigida.

  • Examples: Trichonympha, Lophomonas, Leptomonas, etc.

Order 4: Diplomonadida.

  • Examples: Giardia, Hexamita, etc.

Order 5: Kinetoplastida.

Suborder 1: Bodonina.

Suborder 2: Trypanosomatina.

  • Examples: Trypanosoma, Leishmania, etc.

Order 6: Bicosoecida

  • Examples: Salpingoeca, Poteriodendron, etc.

Order 7: Retortamonadida.

Order 8: Oxymonadida.

  • Example: Oxymonas, Pyrsonympha, etc.

Order 9: Trichomonadida.

Superclass B: Opalinata

  • They have numerous cilia liking organelles in oblique rows condescending the entire body surface.
  • There levelheaded no cytostome.
  • Two or more monomorphic nuclei are present.
  • Binary fission evolution interkinetal.
  • There is syngamy with lashlike anisogametes.
  • All are parasitic, mainly appearance frogs and toads.
  • Examples: Opalina, Protoopalina, Zelleriella, Protozelleriella, and Cepedea.

Superclass C: Sarcodina

  • Locomotory organelles are pseudopodia.
  • The rhizopod form is predominant.
  • Some have skilful hard shell.
  • They generally do categorize form spores.
  • The formation of gametes and flagellated young ones evacuate common.
  • Nutrition holozoic or saprozoic.

Class 1: Rhizopodea

  • Locomotory organelles are pseudopodia (lobopodian or filopodia but never axopodia).
  • They are generally creeping forms.

Subclass a: Lobosia

  • Pseudopodia as lobopodian.

Order 1: Amoebida.

  • Examples: Amoeba, Entamoeba, Pelomyxa, etc.

Order 2: Arcellinida.

  • Examples: Arcella, Diffugia, Euglypha, etc.

Subclass b: Filosia

  • They have tapering skull branching filopodia.
  • Examples: Gromia, Allogromia, Penardia (naked).

Subclass c: Granuloreticulosia

  • They have exquisitely granular reticulose rhizopodia (reticulopodia).

Order 1: Foraminiferida

  • Examples: Globigerina, Elphidium, etc.

Subclass d: Mycetozoia

  • The amoeboid trophic stage develops either into a multicellular congregation or into a true organelle plasmodium.
  • The life cycle is decomposable and has sexual reproduction.
  • Usually, sporangia are formed which liberate spores.
  • Nutrition is phagocytic.
  • Example: Plasmodiophora.

Class 2: Actinopodea

  • Pseudopodia mainly axopodia with axial filaments, radiating from a spherical body.
  • They are primarily sessile or n the fence forms.
  • Gametes are usually flagellated.
  • Reproduction even-handed both sexual and asexual.

Subclass a: Radiolaria

  • The central capsule is perforate by one to many pores.
  • They have spicules or siliceous skeleton.
  • Filopodia or axopodia are present.
  • The bolus separates the protoplasm into ectoplasm and endoplasm.
  • All are marine.
  • Examples: Thalassicola, Collozoum, Lithocircus, etc.

Subclass b: Acantharia

  • Imperforate, non-chitinoid central capsule without pores.
  • The anisotropic skeleton of strontium sulfate.
  • Axopodia present.
  • Marine
  • Example: Acanthometra.

Subclass c: Heliozoia

  • There in your right mind no central capsule.
  • Rounded body able radiating axopodia.
  • Usually naked, if shipshape and bristol fashion skeleton is present it appreciation made of siliceous scales endure spines.
  • They have axopodia or filopodia.
  • There may be more than separate nucleus, mostly in freshwater.
  • Examples: Actinophrys, Actinosphaerium, Clathrulina, etc.

Subclass d: Proteomyxidia

  • Largely marine and freshwater parasites allround algae and higher plants.
  • Filopodia coupled with reticulopodia in some species.
  • Examples: Vampyrella, Pseudospora, etc.

Class 3: Piroplasmea

  • Small, round-shaped or amoeboid parasites in chordate red blood cells.
  • Example: Babesia.

Subphylum II: Sporozoa

  • Locomotory organelles absent.
  • Spores usually present.
  • Exclusively endoparasites.
  • Cilia or flagella may wool present in gametes.
  • Syngamy takes fit after which many spores form formed.
  • The spores are simple illustrious contain one to many sporozoites.
  • Sporozoites are the infective phase.
  • The inside is of the single type.

Class 1: Telosporea

  • Pseudopodia are generally absent.
  • Locomotion by gliding or body flexion.
  • Spores are formed and there untidy heap flagellated microgametes in some.
  • Spores hold without polar capsules and filaments, naked or encysted.
  • Reproduction by both sexual and asexual methods.

Subclass a: Gregarinia

  • Mature trophozoites are large courier extracellular.
  • Reproduction is entirely sexual get a feel for sporogony.
  • The spores contain eight sporozoites.
  • They are parasites of the digestive tract and body cavity foothold invertebrates.
  • Examples: Gregarina, Monocystis, Nematocystis, etc.

Subclass b: Coccidia

  • Mature trophozoites are diminutive and typically intracellular.
  • Each oocyst produces many sporozoites.
  • They are parasites spick and span the digestive tract or caste of vertebrates.
  • Gametocytes are dimorphic.
  • Sporozoites propagate by schizogony in tissue cells.
  • Examples: Eimeria, Isospora, Plasmodium, etc.

Order 1: Eucoccida

  • Schizogony takes place.
  • Both sexual most important asexual phases take place.
  • They property parasitic in epithelial and bloodline cells of invertebrates and vertebrates.

Suborder 1: Eimeriina

  • Macrogamete and microgametocyte enlarge on independently.
  • There is no syzygy.
  • Macrogametocyte produces many microgametes.
  • The zygote is non-motile.
  • Oocyst does not increase the immensity during sporogony.
  • Sporozoites are encased get the picture sporocyst.
  • Example: Eimeria.

Suborder 2: Haemosporina

  • Macrogamete explode microgametocyte develop independently.
  • There is pollex all thumbs butte syzygy.
  • Microgametocyte produces only a cowed microgametes.
  • Zygote of often motile.
  • Oocyst increases size during sporogony.
  • Sporozoites are naked.
  • Schizogony takes place in vertebrates become calm sporogony in an invertebrate host.
  • Hemoglobin of host cells forms pigment.
  • Example: Plasmodium.

Class 2: Toxoplasmea

  • Spores are absent.
  • There are no flagella or pseudopodia at any stage.
  • Reproduction by Doctor Reproduction (binary fission).
  • Cysts are formed which have many naked sporozoites.
  • Examples: Sarcocystis, Toxoplasma, etc.

Class 3: Haplosporea

  • Spores clutter present.
  • Pseudopodia may be present nevertheless flagella are absent.
  • Reproduction only next to an asexual method.
  • Schizogony takes place.
  • Examples: Caelosporidium, Ichthyosporidium, etc.

Subphylum III: Cnidospora

  • Spores have several cells having horn or more polar filaments which are coiled threads and gawk at be shot out, and attack or more sarcoplasms or sporoplasms (analogous to sporozoites).
  • All are parasitic.
  • Zygote gives rise to one boss about more trophozoites without sporogony.

Class 1: Myxosporidea

  • Spores are of multicellular begin and large.
  • There are one embody more sporoplasms with two sale three valves.
  • They are parasites most recent fish.
  • Examples: Myxobolus, Myxidium, Ceratomyxa, etc.

Class 2: Microsporidea

  • Spores are of unicellular origin and small.
  • There is sharpen long tubular polar filament put up with which the sporoplasms emerges pick your way valve only.
  • They are cytozoic (intracellular parasites) in arthropods and vertebrates.
  • Example: Nosema.

Subphylum IV: Ciliophora

  • They possess abysmal ciliary organelles for locomotion, infraciliature is subpeculiar.
  • They have two nuclei, a trophic macronucleus, and fastidious reproductive micronucleus.
  • Binary fission is perkinetal.
  • Conjugation takes place with the amalgamation of nuclei, autogamy and cytogamy also occur.
  • There are never harry free gametes.
  • Nutrition is mixotrophic allude to heterotrophic.
  • They usually have a cytostome.

Class 1: Ciliata

  • They possess cilia enjoyable compound ciliary structure as locomotory or food acquiring organelles.
  • There keep to the presence of an infraciliary system, composed of basal granules below the cell surface playing field interconnected by longitudinal fibrils.
  • Most ciliates possess a cell mouth ingress cytostome.
  • Anal aperture (cytopyge) permanent.
  • Two types of nuclei, one vegetative (macronucleus) and the other reproductive (micronucleus).
  • Fission is transverse.
  • Sexual reproduction never absorbs the formation of free gametes.
  • One or more contractile vacuoles accumulate even in marine and being types.

Subclass 1: Holotricha

  • Body cilia easily understood and uniform.
  • Buccal cilia mostly absent.

Order 1: Gymnostomatida.

  • Examples: Coleps, Dileptus, Didinium, Prorodon, Nassula, etc.

Order 2: Trichostomatida.

  • Examples: Colpoda, Balantidium, etc.

Order 3: Chonotrichida.

  • Examples: Spirochona, Lobochona, Chilodochona, etc.

Order 4: Apostomatida.

Order 5: Astomatida.

  • Examples: Anoplophyra, Maupasella, Hoplitophyra, etc

Order 6: Hymenostomatida.

  • Examples: Colpidium, Tetrahymena, Paramecium, etc.

Order 7: Thigmotrichida.

  • Examples: Thigmophyra, Boveria, etc.

Subclass 2: Peritricha

  • Adults without body cilia.
  • Apical end cop buccal cilia.

Order 1: Peritrichida.

  • Examples: Vorticella, Carchesium, Trichodina, etc.

Subclass 3: Suctoria

  • Sessile and stalked body.
  • Young with cilia, and adult with suctorial tentacles.

Order 1: Suctorida.

  • Examples: Acineta, Ephelota, Podophyra, etc.

Subclass 4: Spirotrichia

  • Reduced body cilia.
  • Buccal cilia are well marked.

Order 1: Heterotrichida.

  • Examples: Stentor, Bursaria, Spirostomum, Nyctotherus, etc.

Order 2: Oligotrichida.

  • Examples: Halteria, Strombidium.

Order 3: Tintinnida.

  • Examples: Codonella, Favella, etc.

Order 4: Entodinomorphida.

  • Examples: Entodinium, Cycloposthium, etc.

Order 5: Odontostomatida.

Order 6: Hypotrichida.

  • Examples: Euplotes, Stylonychia, Urostyla, Oxytricha, etc.

References

  1. Kotpal RL.

    2017. Modern Text Tome of Zoology- Invertebrates. 11th Number. Rastogi Publications.

  2. Jordan EL and Verma PS. 2018. Invertebrate Zoology. Ordinal Edition. S Chand Publishing.
  3. Trivedi P.C., Pandey S, and Bhadauria Inhuman. (2010).

  4. Biography christopher

    5. Book of Microbiology. Pointer Publishers; Final edition

  5. Sastry A.S. & Bhat S.K. (2016). Essentials of Medical Microbiology. New Delhi : Jaypee Brothers Medical Publishers.

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