Protozoa

Protozoa The protozoans are considered as “First animals” (proto – First, Zoan - animals) 2. They are very minute in nature so visible only under microscope. Due to very small in size they are very much in number than other phylum animal (Maxm in number - protozoa) (maxm in species - Arthropods). 3. A protozoan is an independent eukaryotic cell (protist). This is very important to note that, a protozoan is comparable structurally to single cell, but function as a complete body of metazoans or multicellular organism, hence protozoans are Acellular. This term is more current than unicellular. Protozoans are also considered as simplest animals. 4. The body organization of protozoans are protoplasmic grade or sub cellular grade or cell organelle grade. 5. One to several nuclei, mostly same type and in some more than one types nucleus, they are micro and macro types. (Old Classification based upon type of nucleus) 6. Various modes of nutrition are found like heterotrophic – holozoic (animal like), Saprozoic/ saprophytic, parasitic, holophytic-autotrophic (plant like) and same have both type nutrition - Mixotrophic nutrition. 7. Locomotion takes place by pseudopodia, flagella, cilia or none. Protozoans are classified on the basis of locomotary organs (New classification). 8. Body enclosed in Plasmalemma or pellicle or in a shell (Exoskeleton of lime or siliceous) or test. 9. Found both fresh and sea water. Osmoregulation occurs in fresh water forms by Contractile vacuoles. 10. Protozoans are ammenotelic. 11. Reproduction --- Sexual and asexual type. 12. Encysment is the common mode for dispersal and Survival during adverse conditions. 13. Shelled protozoa are Arcella, Difflugia, Elphidium and foraminifererans. 14. Fossilized foraminiferan shells are often associated with petroleum bearing formations. 15. Continuous internal skeleton between ectoplasm and endoplasm is found in radiolarians. 16. A bioluminescent (light production) protozoan is ‘Noctiluca’. The name “Protozoa” was coined by Gold fuss (1817) (father of protozoa) Protozoans were first studied by Leeuwenhoek (1677). He called them “animalcules”. Classification of protozoa A. Older classification –Base on type of nucleus Protozoa Plasmadroma sporozoa cnidosporia chiliophora --Mastigophora or flagelleta --Telosporea --Myrosporea Ciliata Cilia lost in adults --Rhizophora or Sarcodina --Piroplasmea --Microsporea Suctoria B. New classification – Base on type of Locomotary organs Protozoa Sarcomastigophora sporozoa cnidosporia chiliophora --Ciliata --Mastigophora or flagelleta --Telosporea --Myrosporea --Rhizophora or Sarcodina --Piroplasmea --Microsporea --- Oplinata Classification (1) Sub phylum - Sarcomastigophora (1) Locomotion by pseudopodia, flagella or cilia (2) Nuclei one or more (similar when more) (3) No conjugation (a) Class - Mastigophora or flagellate (Whip like) (1) Locomotion by flagella. Flagellates show longitudinal binary fission (2) In same species Exoskeleton present. (3) Same have chlorophyll Example - Euglena, Trypanosoma (sleeping sickness), Leishamania. Euglena Link between plant and animal. Having Chlorophyll a and b for photosynthesis. Starch stored in paramylene bodies. During dark ness nutrients are absorbed by general body surface not by cytostome. Mixotrophic nutrition. Longitudinal binary fission takes place. In longitudinal binary fission, first of all flagella divided than division proceed to posterior side. Flagella one or two Para flagellar body act us photoreceptor. Trypanosoma Trypanosoma show polymorphism. They are found in four forms on the basis of forms of body and arrangement of organelles. 1. Tropica form 2. Leptomones form 3. Crithedial form 4. Leishamania form Trypanosoma is digenetic found in man and domestic animals. Insects serve as intermediate host or vector hosts. Man and domestic animals infected by bite of tse - tse fly (Glossina). With bite of glossina fly leishmania form pass in lymph and blood of host and converted in to trypanosomal form. All the four forms are found in the secondary host (domestic animals) but only Trypanosomal and leishmania forms in primary host. Diseases (1) Sleeping sickness: Trypanosoma gambiense found in cerebrospinal fluid of man and cause sleeping sickness. It is also found in cattle’s and horses and cause surra and Nagna diseases. Trypanosoma gambiense found in west and central Africa and transmitted by Glossina polpalis. Its reservoir host is antelope, pig and domestic animals. Trypanosoma rhodensiense found in East Africa and transmitted by Glossina marsitans. It is more virulent with higher mortality. Reservoir host - which is immune for infection (2) Chagas diseases: It is caused by Trypanosoma cruzi in south and Central America. The inter mediate host of this disease are triatomid bugs. Leisamania This is other flagellate found in two forms ------ 1. Leptomones 2. Leishmania Diseases (a) Kala azar or visceral leishmaniases: It is caused by Leishamania Donovani. This disease is transmitted by sand fly (phlebotome). In this disease there is an enlargement of spleen together with fever. Kala azar also known as ‘Dum Dum fever’. Reservoir host - Dogs and Cats (b) Oriental Sore or cutaneous leishamaniases: It is caused by Leishamania Tropica and transmitted also by sand fly. (c) Espundia or Bubos (Naso-oral or muco-cutaneous leishmaneases): It is caused by Leishamania braziliensis. Sand fly fever is a viral disease and it is also spread by sand fly. Giardia – Other mastigophoran or flagellate parasite cause diarrhea. Flagellate are of two types ---- (i) Phyto-mastigina – with chloroplast, plant like. Euglena, Chlamydomonas (ii) Zoo-mastigina - with out chloroplast, animal like. Trypanosoma, Leishamania. (b) Class - Sarcodina or Rhizopoda (1) Locomotion by pseudopodia. Example – Amoeba, Entamoeba (c) Class - Opalinata (1) Locomotion by cilia [Note - previously placed with ciliates but now as a separate class because their nuclei (several) of one kind only and no conjugation (2) Found as Intestinal parasites of amphibians]. (2) Sub phylum - Sporozoa (1) All Endo-parasite (2) No locomotary organs (3) Speculation is commonest mode of reproduction (4) Spores with out polar filaments. These are divided into two classes on the basis of shape of Sporozoite. Class – Telosporea - Sporozoite elongated and with pellicle. Example - Plasmodium (malarial parasite). Monocystis (parasite in seminal vesicles of Earth worm) (b) Class – Piro-plasmea 1. Sporozoite naked and no pellicle. 2. Intra cellular parasite of RBC of cattles and causing Texas cattle fever. Example - Babesia (3) Sub phylum - Cnidosporia (1) Intra cellular parasites (2) No locomotary organs (3) Spores with polar filaments Divided in to two classes on the base of spore formation. (a) Class - Myxosporea Spores with 1 to 4 polar filaments, several nuclei and bi or tri-valve. Example - Ceratomyxa (b) Class - Microsporea Spores uni-nucleate and uni-valued. Example - Nosema (4) Sub phylum - Ciliophora (1) Locomotary organelles cilia (2) Transverse binary fission takes place. (3) Nuclei two types or more. (a) Class - Ciliata All ciliophara includes. Example – Paramecium, stentor, Balantidium, Ephelota, Vorticella Balantidium: This is a ciliate parasite found in colon and Caecum of man, monkey, pig etc. causes Balantidiosis or Balantidial dysentery. This parasite having two contractile vacuole and also have vestibule cytostome and cyto-pharynx with similar cilia to those on outer surface. Study of protozoa - protozoology Father of protozoa - Gold fuss. Amoeba proteus Amoeba proteus is a sarcodian protozoan. It was discovered by Rosen Hoff in 1755. The meaning of ‘Amoeba’ is ‘to change’; the term ‘proteus’ refers to a ‘sea god’ who could change the shape. Habit and habitat It is widely distributed. Found in both fresh and sea water and also found in moist soil. It is rarely found in free moving water. It required a substratum to glide on from place to place. It is abundant in those waters in which bacteria and organic substances like aquatic vegetations, leaves etc are present. Size and shape It is unicellular microscopic animalcule of size 0.2 to 0.5 mm in diameter. It’s out line of body continuously changing due to formation of finger like process called pseudopodia or false feet. The pseudopodia are of finger process with blunt end so called lobopodia. In a moving amoeba new pseudopodia form at the direction of movement and old or withdrawal pseudopodia present at posterior end called as Uroid. The amoeba body divided in to three parts ------------ (1) Plasma membrane (2) Cytoplasm (3) Nucleus (1) Plasma membrane: Amoeba is said to be “naked” like ordinary animal cell. It is tri-laminar unit membrane of fluid mosaic architecture and also possesses extremely fine, fiber like out growth called micro villi. It is selectively permeable plasma membrane slip over hyaline layer. (2) Cytoplasm: It is divided in to two parts ------------- Ectoplasm Hyaline layer – clear, colourless, watery fluid layer Cytoplasm Plasma gel – fibrous, granular, viscous jelly like layer Endoplasm Plasma sol – cyclosis takes place Following structures present in cytoplasm includes nucleus and cytoplasmic organelle and three type of vacuole present in it (i) Contractile Vacuole: A contractile vacuole present in cytoplasm which is enclosed by condensation membrane. Numerous mitochondria present around it. Its main function is Osmoregulation. (ii) Food Vacuole: They are related to nutrition, not permanent structure. (iii) Water Vacuole: Several small, spherical, non contractile, colourless water vacuoles. Their significance is yet unknown. (3) Nucleus: Amoeba has single, disc – shape, Concavo Convex nucleus. Its nucleo plasm contains several nucleoli and about 500 scattered chromatin granules called chromidia. It plays a vital role in metabolism, reproduction and heredity. When an amoeba cut into number of piece, the every piece which contains any part of nucleus converted into complete amoeba while other portions are degenerated. Same Crystals of Carbonyl di-urea called bi-uretes and tri-urets are also found in cytoplasm. They are excretory product of carbonyl di-urea. Locomotion in amoeba Amoeba crawls about 0.02 to 0.03 mm per minute. Pseudo podia form at any place of body, with reference to the formation of pseudopodia, following theories have been given for Explaining Locomotion in amoeba ----------- (1) Adhesion theory: According to this theory amoeba moves like a drop of water streaming out in the path of greatest adhesion. (2) Contraction theory: Heitzmann advocated that amoeba was a 3-dimensional network (Reticular theory of cytoplasmic structure) of live contractile fibers whose contraction brings the formation of pseudo podia. Schultze postulated “Contraction at rear end pushed or “squeezes” sol ahead. (3) Surface tension theory: This was given by Berthold according to this theory pseudopodia formed at point of lowered surface tension. Butschli and Rhumber supported this view. (4) Rolling movement theory: This theory was given by Jennings. He placed a Carbon particle upon the amoeba Verucosa and see that amoeba moves just like a rolling ball. This movement does not show by other species. (5) Walking movement theory: It is given by Dellinger. He show amoeba at lateral side and stated that formation leg like structures on which amoeba walk. (6) Pressure or Ecto-plasmic Contraction or Sol gel theory: Hyman and Schaudinn suggested that conversion of ectoplasm takes place into Endoplasm and vice - Versa was chief base of amoeboid movement. Later actual work on this view was done by mast and panting. According to their theory sol and gel are inter convertible. At progressing end where pseudopodia is being formed Gelation takes place (formation of gel take place from sol) while at the rear end solation takes place (formation of sol from gel) and the contraction at rear end pushes plasma sol in forward direction and it produce pseudopodia. (7) Molecular folding unfolding theory: It is given by Gold acre and loach. They found that protein molecules are well arrange in gel state and folded and scattered in sol state. Thus this theory further explains sol - gel theory. Huxley said that protein molecules involve in solation and elation are similar to action and myosin of muscles fibers and their folding - unfolding in vacuoles great expenditure of ATP. (8) Fountain zone contraction theory: It is given by Allen. According to this theory an axis of gel is found in centre in continuation of progressing end. Streaming of cytoplasm gives fountain like appearance at progressing end. (9) Contraction Hydraulic theory: Given by Ronaldi and john according to this pseudopodia is formed at the place of highest hydraulic pressure or minimum resistance of plasma lemma. Nutrition in Amoeba Amoeba is omnivorous Feeds upon bacteria, diatoms etc. Holozoic (ingest food). Nutrition takes place by following methods (1) Import: This is passive mode of food ingestion. (2) Invagenation: In this type of nutrition in folding of plasma membrane takes place. (3) Circumfluence: A cup - shaped cavity is formed around food in circumfluence. This mode is used for Non - motile food like algae. Food - Cup is formed in this type of Nutrition. (4) Circumvallation: In this process finger like villi form around food. This is used for motile food. Circumfluence Circumvallation 1. It is for non motile food -algal filament 1. Used for motile (active) food like bacteria 2. Slow 2. Fast Pinocytosis = cell drinking for liquid food Phagocytosis = cell eating for solid food Digestion of food This takes place inside food vacuole. These Vacuoles are analogous to alimentary canal of higher animals. But difference of between two is that digestion in food vacuoles is intra cellular type and digestion in alimentary canal is extra cellular type. Digestion takes place in two phases - first acidic and second alkaline. In acidic phase no digestion of nutrients occur, in this phase only food becomes loose and soft. when Lysosome attached to food vacuole medium become acidic. Amoeba can digest protein, fats or lipids but digestion of carbohydrate is doubtful By the cyclosis distribution of digested food takes place. Cyclosis takes place in sol part. Egestion: Elimination of undigested part of food from body. Excretion: Elimination of nitrogenous by products of metabolism from body. Respiration: gaseous exchange occurs through plasma lemma by diffusion or by general body surface. Excretion: Elimination of metabolic nitrogenous waste products form general body surface known as excretion. Possibly, amoeba store, its nitrogenous products in the form of crystals which is made up of carbonyl di-urea in the form of bi-urets and tri-urets. Osmoregulation or water balance Fresh water is hypotonic to the cytoplasm of amoeba; hence, there is continuous endosmosis (inflow of water into the body) of water takes place. Some water also enters into body by food vacuoles and metabolic reaction, due to this water accumulation, the amoeba, can burst or swell. To control and elimination of excess of water, Osmoregulation occur. The membrane enclosing contractile vacuole is called condensation membrane, which is similar to plasma membrane. Numerous mitochondria lie scattered around the condensation membrane. The contraction of contractile vacuole at the time of discharge of water is also called systole (disappearance) white its enlargement on accumulation of water as diastole (appearance). Systoles and diastoles of contractile vacuole are analogues to the processes of heart. Generally contractile vacuole lies at posterior end. Function of contractile vacuole is Osmoregulation (Not excretion as was supposed earlier). If a fresh - water amoeba is placed in isotonic solution this vacuole is not formed, like wise, when a marine amoeba is placed in fresh water, it develops a contractile vacuole. Excretion: Amoeba is Ammenotelic or its major excretory waste is ammonia. Ammonia diffused out through plasma lemma. Amoeba also contains bi-urets and tri-uretes of carbonyl di-urea, which are crystal of excretory matter Behavior of Amoeba or Response of Amoeba (1) Thigmo-taxis or mechanical contact or response to touch Positive for food Negative for other objects (2) Photo-taxis (light response) Positive for Normal light or dim light Negative for sudden dim or bright light (3) Galvano taxis Positive Anode to cathode It becomes stationery when high field is maintained or rest between anode and cathode. (4) Thermo taxis (temperature response) 20°C to 25°C is best suitable for amoeba (optimum temp.) more then 30°C or very / how temp is fatal for him. (5) Chemo-taxis (Chemical response) Negative Reproduction in Amoeba: Amoeba always reproduces by asexually by following methods --- (1) Binary fission It is simplest cell division and commonest mode of reproduction in amoeba. This takes place during favourable condition (plenty food and suitable temperature). In this condition 500 to 600 chromidia appear as duplicated chromosomes in Nucleus. (2) Sporulation Some species of amoeba reproduce by sporulation. This takes place in unfavorable condition. In sporulation about 200 spores are formed. (3) Multiple fission and Encystment In unfavorable condition amoeba reproduce by multiple fission or encystment and forms 500 amoebae. Cyst is enclosed by the number of layered. Germination of amoebae and cyst occurs during favourable condition. Sporulation and multiple fission are helpful in passing unfavorable condition (perenation). (4) Regeneration Amoeba has tremendous power of regeneration, if it cut in to small pieces, each piece, which containing a part of the nucleus, rapidly regenerates in to a complete amoeba. There is no differentiation of Somato plasm and germ plasm in amoeba. The whole body is passed in to daughter amoeba; hence no dead body is seemed, amoeba regarded as immortal. The total size of two daughter amoebae is slightly exceeds that of parent amoeba. Entamoeba - There are three species of Entamoeba. (1) E. histolytica (2) E. gingivalis (3) E. coli Entamoeba histolytica E. histolytica was discovered by Lamble and named by Losch. This is found in proximal part of colon (part of large intestine). Its size about 20u – 30u. It possesses single pseudopodium or monopodium. E. Histolytica is dimorphic (found in two forms). 1. Large - Magna 2. Small - Minuta The magna form is typical form while minuta is pre-cystic the encystment takes place around minuta form only. In Entamoeba no contractile vacuole are present. The reserve food material of Entamoeba is in the form of chromatids bodies of glycogen. E. histolytica makes funnel shaped ulcers to feed on R.B.C. and causes amoebic dysentery (amoeboesis). Entamoeba are monogenetic (complete their life cycle in single host). Infection takes place by contaminated food or water. All the carrier of Entamoeba does not develop amoeba dysentery, in healthy people the loss is made good. Amoebic infection generally causes “recurrent diarrhea”. Amoebic dysentery occurs only in severe Cases. The Cyst is tetra nucleated in Entamoeba histolytica; they are passed out with human fasces. The cysts on reaching the colon of new host release single Meta cystic amoeba (having four nuclei). This metacytic amoeba gives rise eight amoeba. Preventions: Most effective drug for amoebiosis is Flagyl or Metrogyl. Metronidazole and chloroquine and its derivatives are common drugs for treatment of amoebiosis. Other common drugs are Abodolgyl, Amebamagma, Amibactin, Biomebic, Dependal, Diodoquin, Entamizole, Enteroquinol, Flagyl, Metrogyl, TRini, Tridazole, TDF-Forte etc. If infection of Entamoeba occur in liver, chloroquine in used. Entamoeba Gingivalis It is found in gums of dog, cat, horse, monkey, man etc. It is smaller in size about 10 – 20u feeds on WBC. No cyst format, infection takes place by kissing. Also considered to be cause ‘Pyorrhea’, it is disease condition of gum. Now it is thought that pyorrhea is cause by certain bacteria and amoeba like protozoan – Trichomonas tenax. E. coli It is also found in human colon, it is harmless to man and considered “commensel pathogen”. The Cysts of E. coli are 8 nucleated, it infection also takes place by contaminated food and water. E. coli is largest among the three entamoebae about 20 – 40u in size. It has no distinction of ectoplasm and endoplasm. Binary fission and encystment are the two modes of reproduction in Entamoeba. Pathogen is that which causes diseases. Thus only E. histolytica is pathogenic. The pathogenecity of E. gingivalis is not confirmed while E.Coli is non - pathogenic. Plasmodium (Malaria parasite) The reservoir host of plasmodium is monkey. Plasmodium belongs to Sub-phylum - Sporozoa of class - Telosporea. It has four species ---------- (1) P. Vivax (2) P. Ovale (3) P. falciparum (4) P. malariae Plasmodium infects mostly people of tropical countries. All the species except P. ovale are widely distributed. P. ovale is found in South America and West Africa. P. Vivax is commonest species of plasmodium. The malaria - means Mal - foul, aria = air. It was thought in ancient time that malaria is caused by foal air, arising from marshes place. Lancisi was first correlate malaria with mosquitoes. Charles Laveran first discovered plasmodium in human blood (RBCs). Sir Ronald Ross in 1877 discovered oocytes of plasmodium upon stomach of female anopheles, while working in India. His noble prize in 1903. Golgi worked out detailed cycle of plasmodium in humans. Grassy described complete life cycle of plasmodium in mosquito. Incubation period The time interval between the infection and the appearance of the disease is called incubation period. In relation to plasmodium, it differs from species to species. P. Vivax – 14 days P. Ovale – 14 days P. falciparum - 12 days P. malariae - 28 days Malaria Tertiary Quatanary Quatidian Fever relapse after Fever relapse after Fever come daily due to a gap of 48 hours a gap of 72 hours mixed infection P. Vivax P. malariae Tertiary Malaria Benign Mild Malignant P. Vivax P. ovale P. falciferum The malignant tertian malaria caused by P. falciparum. It is also called Cerebral malaria or Astevo autumnal malaria or Fernicious malaria or Black water fever. Plasmodium is digenetic - It has two hosts human and female anopheles. Out of the two hosts - man is considered to be primary host because adult stage of parasite (trophozoite) is found in its RBCs, female anopheles is considered secondary host because embryonic (sexual) state are found in it. Certain authors, how ever regard mosquito as primary host due to presence of sexual stages in it, the former view is more accepted. Life cycle - Life cycle of plasmodium involve following phases ----------- Schizogony - Liver and RBCs of man Gamogony – Stomach of female anopheles Sporogony - Stomach of female anopheles SCHIZOGONY IN MAN Infection: When infected Anopheles sucking blood of human being it first introduces saliva in blood to prevent its coagulation and also several sporozoides introduce in blood. Male mosquito can not infect human beings because they lack maxillae and mandibles for piercing human skin. Natural food of mosquitoes is plant juice; females require blood meal for egg laying. Male mosquitoes survive for a week only, while female mosquito for months. Male die after impregnating the females while female die after laying full quota of their eggs. In side culex plasmodium can not survive. Infective stage of plasmodium Sporozoite with in half an hour of infection reaches from blood to liver and start schizogony. Liver schizogony is also divided in to the following phases ---------- 1. Exo erythrocytic cycle 2. Erythrocytic cycle In liver cells sporozoides actively feed and converted into large sized cryptozoide. Cryptozoide are multinucleated schizont. In later stage cryptozoid divided into uni-nucleated 1000 cryptomerozoides by special type of multiple fission, called schizogony. This schizogony is called exo-erythrotic cycle Due to pressure of cryptomerozoides liver cell rupture and cryptomerozoides librated into sinusoid of liver. These cryptomerozoides invaded new fresh liver cells and continue exo-erythrotic cycle. Some cryptomerozoides also invading upon RBCs and start erythrotic cycle Pre-erythrotic cycle: The first exo-erythrotic cycle in liver after which parasites re-appear in blood is called pre-erythrocytic cycle. Cryptomerozoides of pre-erythrotic cycle invade fresh liver cells and converted in to metacryptozoides or phanerozoides. These metacryptozoides form two types of zoides ---- 1. Small sized – Micrometacryptozoides – 100 to 10,000 2. Large sized – Mecrometacryptozoides – 64 These micro and macro cryptozoids are invaded new liver cells and RBCs. Pre-patent period: The time interval between inoculation and initiation of erythrocytic cycle is called pre-patent period. Exo-erythrocytic cycle is absent in plasmodium falciparum. Erythrocytic cycle This cycle takes place in RBCs and begins when a cryptomerozoide or meta-cryptomerozoide enters into RBC. This cycle divided into four stages ------- (1) Signet ring stage: After entry of merozoide into RBC, it is become a round disc like young trophozoid. As it grows a large non-contractile vacuole appears in to its centre and pushes the cytoplasm and nucleus to a thin peripheral layer and taking a shape of signet ring. (2) Amoeboid stage: Soon vacuole disappears and trophozoid become amoeboid. This amoeboid trophozoid start actively feed up upon cytoplasm of host RBC. During its active growth period ‘Haemozoin granules’ are formed by residual haemoglobin inside cytoplasm of parasite or in trophozoid and ‘Schuffner's dots’ are found inside infected RBCs and it is toxin released by the parasite. Schuffners dots in P. Vivax, Ziemann’s dots in P. malariae and Maurer’s dots in P. falciparum. (3) Erythrocytic schizogony and incubation: After complete development of trophozoid repeated mitotic division takes place and 8 to 26 daughter nuclei are form. This condition preparing trophozoid for schizogony and this trophozoid refer as erythrocytic schizont. This schizont forms 8 to 26 new merozoides or schizo-zoids. On completion of schizogony schizont and RBC are burst and release merozoids in blood. These merozoids invade new RBC to repeat erythrocytic cycle. Releasing of toxic substance cause malarial fever. Incubation period - It is period of infection and appearance of characters. It is combination of prepatent period and Erythrocytic cycle period Incubation period = prepatent period + Erythrocytic cycle period The schizogony taking place in side RBC is called erythrocytic cycle, it takes 48 hours in P. Vivax, P. ovale and P. falciparum while 72 hours in P. maleriae. (4) Development of Gametocytes: After number of erythrocytic cycles some merozoids are develops in to deferent manner. During development these merozoids not under go signet ring stage and form gametocytes. Gametocytes are essentially trophozoid destined to produce gamete; they are of two types - micro gametocytes and macro gametocyte. Infective stage to mosquito is Gametocyte, which are usually produced during night on account of a biological clock inside parasite to facilitate the infection. On reaching inside stomach of mosquito all stages of plasmodium except gametocyte are digested. Life cycle of plasmodium in mosquito (Sexual cycle) Infection in mosquito: When a female anopheles sucking blood of infected human it receive different stages of erythrocytic cycle. In gut all stages except gametocytes are digested. Gametocytes produce gamete; they are of two types - micro gametocytes and macro gametocyte. The development of gametocyte requires low temperature. Gamogony in mosquito It takes place inside lumen of mosquito stomach. 6-8 sperms are produced from microgametes by a peculiar process - exflagellation; it is usual meiosis or reduction division. Female gametocytes produce from macro gametocytes and also form polar bodies by meiosis; hence a single ovum is produced by each of them. Fertilization takes place inside stomach. The zygote gets elongated to form ookinete, which enters stomach wall to develop into oocysts. Sporogony in wall of mosquito It takes place inside oocysts lying upon stomach of mosquito about 10,000 sporozoides are produced which are released into haemo coel or body cavity of mosquito, from there they penetrate into salivary glands and remain stored there making the mosquito infection. Symptoms and phase of malaria Prodromal symptoms: In a typical malarial infection, mild symptoms appear even during incubation period. These include nausea, loss of appetite, constipation and insomnia (sleepless ness). Mouth often feels dry, tongue may be thickly coated. Headacache, muscular pain and aches in joint also develop. Paroxysm: It is actual clinical attach of malaria. It begins after a few earlier erythrocytic cycles and repeated after every cycle. The paroxysm results due to sufficient accumulation of haemozoin and toxins release in blood. Duration of paroxysm varies person to person. It includes three phase ------- (i) Rigor stage: In this stage patient experiences terrible chill and shivering, rapid pulse and breathing, severe headache, nausea and vomiting. (ii) Febrile stage: Shivering sub sides in about an hour and body temperature raises upto 1040 to 1050F. (iii) Defervescent stage: After few hour profuse sweating starts, temperature of body steadily drop and apart from exhaustion and weakness, the patient feels healthy. A gradual recovery from malaria may be due to effective immunity developed by patient. Treatment or therapy Quinine is the commonest, oldest drug for treating malaria is derived from the bark of cinchona tree. This drug destroys all the stages present in blood. Quinine is not effective against stages of parasite found in liver. Other drugs like primaquine and Daraprin kill the parasite in liver. Cervical malaria is drug resistant or fatal. Metakelfin is used to treat diseases caused by P. falcifeparum Spraying of oil upon stagnant water controls malaria because mosquito larvae can not breathe and die. NMEP stands for National malaria Eradication programme in year 1953. There is a comeback of malaria on account of resistance developed by mosquitoes against DDT. Biological control of malaria involves introduction of Larvivorous fishes in aquatic bodies because they feed on mosquito larvae - eg. Gambasia fish. Nitella (algae) cause death of mosquitoes in ponds hence used in control of malaria. Plasmodium is non pathogenic to mosquito host. Malaria disease consider as ‘disease of Peru’. Entamoeba histolytica - Coelozoic Plasmodium - Cytozoic Trypanosoma - Histozoic (found in cells or tissues) PARAMECIUM It is discovered by Hill and commonly known as ‘slipper animal’ or ‘Chousson of joblot’. Its body has fixed shape and enclosed in a pellicle. It contains two nucleuses - one mega nucleus and one micro nucleus in Paramecium cadatum, two micro nucleuses in Paramecium aurelia and several micro nucleuses in Paramecium multinucleateatum. Its size is about 0.08 mm to 0.35 mm. Its anterior end is bluntly rounded and posterior end is conical and pointed. The colour is pale yellow and green in Paramecium bursaria due to presence of green alga zoochlolerella in endoplasm. There are two contractile Vacuoles surrounded by several. radiating canals pellicle of paramecium shows hexagonal facets from the centre of each arises a cilium (having usual 9 + 2 arrangement) At the base of each hilum lies a granule called based granule. Contractile vacuole Contractile vacuole of paramecium are osmoregulatory like that in other protozoans, they are associated with 5 to 12 feeder canals lying around them. It possess pore for dischargetion, in pellicle. The posterior contractile vacuole works faster than the anterior. The main vacuole the feeder vacuoles, systole and diastole alternately. Structure of Trico-cyst Alternating with cilia Tricho-cysts are found, it is develop from basal granules. These are bottle shaped structure lying perpendicular to the pellicle and distinguishable in to three parts – 1. Body or shaft 2. Barb or spike 3. Cap. Tricho-cysts are structures of defense. They also help anchoring, food capturing and react to injury. Nucleus Paramecium is hetrokaryotic, it posses dimorphic nucleus, one large sized macro nucleus and one micro nucleus. One mega nucleus and one micro nucleus in Paramecium cadatum present, two micro nucleuses in Paramecium Aurelia present and several micro nucleuses in Paramecium multinucleateatum present. Macro nucleus of paramecium is made up of Tropho-chromatin (More RNA containing) and concerned with vegetative function only. The micronucleus (one or more) are male up of Ido-chromatin (more DNA containing) and are concerned with reproduction. Locomotion The anterior and of paramecium is blunt while the posterior conical and bear a tuft of longer cilia (caudal tuft). The cilia are principal Locomotary organs in paramecium. These are also helpful in feeding and sensory reception. Paramecium swims actively at a normal rate of 1.5 mm per second by cilia. Each cilium has an effective stoke and a recovery stoke, one offer the other. During effective stoke cilium remains contract like a stiff rod and it is slight curved towards the direction of beating and slow water move. During recovery stroke cilium remains flexed and straight and moves back to its normal position five times faster. In this no water is pushing. All cilia beat at the same rate but not simultaneously or together. There is Synchronous beating of cilia in transverse row, white metachronol beating in longitudinal row. Paramecium takes a spiral course of forward movement in antilock wise manner in its way, it is called gyration and simultaneous its body rotates on its body axis, it is called rotation. Paramecium can moves back ward in right hand side moving (Clock wise manner). Nutrition Paramecium is holozoic. It is feed upon bacteria, diatoms, yeast, uni-cellular algae, micro-organisms and even non living organic particles. Feeding Paramecium actively searches food. During feeding cilia beating is changed such a way as to create a continuous conical current of water called ‘vortex’. The particles cone with this current large particles, those are useless are remove and thrown by ciliary tract of vestibule. Hence paramecium is ‘filter feeder’. The buccal cavity of paramecium have an incoming ‘feeding current’ and an out going ‘rejection current’ of water exhibits On right side, near its middle paramecium possesses an oral groove, it leads in to Vestibule. The vestibule open into a buccal cavity, it is demarcated by endoral membrane, this membrane have capacity to selection and rejection up coming particles. In side buccal cavity certain structure are also found. These are derived from modification of cilia – these structures are panniculous of two pieces - dorsal and ventral and quadrulous of four ciliated tract. All these structure help in directing food particles from buccal cavity to cyto-pharynx via cytostome. Cilia are absent in cyto-pharynx. Those animals which feed by using cilia are called “Ciliary feeder”, they may or may not be filter feeder (In filter feeders a porous or reticular plate is present to filter the food). Cyto-pharynx terminates at end oral fibers which helps contracting (punching off) of food vacuole. The movements of food vacuole inside endoplasm of paramecium are called “cyclosis”. The food vacuole is analogous to alimentary canal of higher animals having acidic medium first and alkaline later (after association with Lysosome). Egestion takes place through a permanent pore called cytopyge or cytoproct. Cytopyge lying on right hand side, little a head the posterior end. Excretion is ammenotelic - paramecium excretes ammonia, it takes place through general body surface and also associated by contractile vacuole. Reproduction in paramecium Most common method of reproduction in paramecium is binary fission; several other ‘nuclear regeneration processes’ also occur at a interval, to maintain the vitality of fission. The binary fission in paramecium takes place transversely (longitudinal in flagellates). Out of the two parts formed the anterior is called proter while posterior is opisthe. Paramecium has eight species. Nuclear re-organization in Paramecium There are of following types - (1) Conjugation ------- (2) Autogamy Sexual (3) Cytogamy ------- (4) Endomixis ------- (5) Hemixis -------- Asexual All these process takes place after many binary fissions and their significations of this division is rejuvenation. (1) Conjugation It takes place between members of same species, same variety but different mating types. Each variety has two mating types. Conjugation takes place in paramecium caudatum. In conjugation process ------------------ Two paramecium of same species, same variety but different mating types come close. Its macro nucleus degenerated and micro nucleus divided in to two nuclei. And further division give rise four micro nuclei. Out of four nuclei, three are degenerate and a functional nucleus is remains. The functional nucleus divided unequally and forms a small migratory male (♂) pro-nucleus and a large stationary female (♀) pro-nucleus. After formation of male and female pro-nuclei, syngamy takes place by cyto-plasmic bridge. Exo-conjugation occurs. To (11) stages Amphi-nuclei divided meiotic division and form eight haploid nuclei. (12) The four nuclei become enlarge as macro-nucleus and in remaining four nuclei, three are degenerated. Only one remains as micro-nucleus. (13) to (14) By two subsequent division, four paramecium are form. Each paramecium has one macro and one micro nucleus. (2) Autogamy It is takes place in Paramecium aurelia. Paramecium aurelia have two micro and one macro nucleus. By autogamy two parameciums are formed by single paramecium. In Autogamy process ------------------ (1)Two paramecium of come close with two micro and one macro nucleus. (2) Its macro nucleus degenerated and micro nucleus divided in to eight nuclei. (3) Out of eight nuclei, seven are degenerate and a functional nucleus is remains. (4) The functional nucleus divided and forms two migratory male (♂) pro-nucleus and two stationary female (♀) pro-nucleus. (5) After formation of male and female pro-nuclei, syngamy takes place and two Amphi-nucleuses is form. (6) These two Amphi-nucleus divided unequally and form two macro and two micro nucleus (7) The micro nucleus is further divided and total four micro nucleuses are form. (8) The paramecium is divided and two daughter paramecium are formed. (3) Cytogamy This is intermediate of conjugation and autogamy like conjugation in this two paramecium are required and like autogamy syngamy occur between male and female pro-nuclei in some individual. (4) Endomixis: It is considered asexual because no syngamy in occur in this process. This process also recorded in Paramecium aurelia. (5) Hemixis: In this process micro nucleus play no role and reorganization of only macro nucleus takes place. The macro nucleus first breaks into pieces, some pieces are disappearing and remaining pieces fused and form macronucleus. Micro nucleus remains as purification of macro nucleus. Some born (1937) discovered cyto plasmic inheritance of kappa particle in paramecium. Other particles like Lambda (), Mu and Pi particles in paramecium. *** 9 DR. RATHOR BIOLOGY CLASSES 64 MADHAV KUNJ PRATAP NAGAR AGRA. Nuclei more Nuclei one Macro nucleus - Trophic or Vegetative function Micro nucleus - Reproductive function Malarial day – 21 August Amoeba is cultured in laboratory by ‘Hay infusion method’.