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Stavropol State Medical University” Ministry of Public Health of the Russian Federation The federal budgetary educational establishment of higher education “Stavropol State Medical University” Ministry of Public Health of the Russian Federation Biology Department Makarenko E.N., Erina N.V., Kopteva T.S., Nikolenko T.S. Educational manual for students of the English-speaking Medium of Medical University Stavropol, 2017 1 УДК: ББК М Макаренко Э.Н. МЕДИЦИНСКАЯ ПРОТОЗООЛОГИЯ: учебное пособие для студентов англоязычного отделения медицинского вуза (на английском языке) / Э.Н. Макаренко, Н.В. Ерина, Т.С. Коптева, Т.С. Николенко – Ставрополь: Изд-во СтГМУ. – 2017 – 57 с. Пособие предназначено для студентов первого курса. В нем рассматриваются общая характеристика типа Простейшие, особенности классов, описываются отдельные виды по общему плану: • систематика паразита; • характеристика вида; • географическое распространение; • хозяева для паразита; • переносчики; • жизненный цикл паразита (инвазионная, патогенная стадии для человека); • способ заражения; • локализация в организме хозяина; • название заболевания; • клинические проявления; • диагностика; • характеристика заболевания. Цель пособия – научить студентов первого курса находить взаимосвязь между медицинскими и биологическими аспектами. Показать, как знания жизненного цикла паразита используются в ответах на медицинские вопросы, такие как патогенез (механизм развития) заболевания, клиника и диагностика. Пособие содержит много иллюстраций, диаграмм и таблиц, что поможет иностранным студентам при подготовке к практическим занятиям и экзамену по биологии. Рецензенты: Заерко В.И., директор Ставропольской биофабрики, доктор ветеринарных наук. Знаменская С.В., кандидат педагогических наук, доцент, зав. кафедрой иностранных языков СтГМУ, декан факультета иностранных студентов. УДК: ББК М Рекомендовано к печати редакционно-издательским советом СтГМУ. © Ставропольский государственный медицинский университет, 2017 2 Федеральное государственное бюджетное образовательное учреждение высшего образования «Ставропольский государственный медицинский университет» Министерства здравоохранения Российской Федерации Кафедра биологии Stavropol State Medical University Biology Department Макаренко Э.Н., Ерина Н.В., Коптева Т.С., Николенко Т.С. Makarenko E.N., Erina N.V., Kopteva T.S., Nikolenko T.S. МЕДИЦИНСКАЯ ПРОТОЗООЛОГИЯ Учебное пособие для студентов англоязычного отделения медицинского вуза (на английском языке) MEDICAL PROTOZOOLOGY Ставрополь, 2017 Stavropol 2017 3 P R O T O Z O A Protozoans were first discovered by Anton Van Leeuwenhoek (1632-1723) in 1671. Minute unicellular organisms which can be observed only under a microscope are included under this phylum. Goldfuss (1817) coined the word “Protozoa” from the Greek words: “protos” – first and “zoon” – animal. Von Siebold (1845) recognized them as unicellular organisms. Protozoal organism consists of a single “cell-like unit” which is morphologically and functionally complete. The differences between protozoa and metazoa are as follows: PROTOZOA METAZOA Morphology Unicellular Multicellular A single “cell-like unit” A number of cells, making up a complex individual Physiology A single cell performs all the functions: Each special cell performs a reproduction, digestion, particular function respiration, excretion etc. General Characters of Protozoa Protozoans are cosmopolitan in distribution and live in sea water, freshwater, and moist places (Diagram #1). Some are solitary, some colonial. Some are free- living. But some live as parasites on and in plants, animals and human beings. Some lead a sedentary life. They have (different) various shapes and symmetries. Some are spherical, some oval, some bell-shaped and some spindle-shaped while some are shapeless. Some are asymmetrical while some exhibit radial or bilateral symmetry. All protozoans are unicellular. Though the body is made up of only a single cell, it is capable of carrying out all the metabolic activities. The structure of a protozoal cell is composed of a plasma membrane (1), a cytoplasm (2) and one or more nuclei (3). ① Cytoplasmic body is bound by plasma membrane or protecting membrane called pellicle. It supports cell membrane and help to keep the cell form. Some have an exoskeleton made up of CaCO3 or silica. ② Cytoplasm may be divisible into two portions: Ectoplasm. The external hyaline portion; its function is protective, locomotive and sensory. Endoplasm. The internal granular portion; its function is nutritive and reproductive. Cytoplasm contains a number of organelles, which perform various metabolic activities. 4 ■ Locomotor organelles are pseudopodia, cilia and flagella. They are absent in some parasites, as in Sporozoa. Pseudopodia Prolongation of temporary Seen in class Rizopoda ectoplasmic process (Sarcodina) Long delicate thread-like Seen in class Zoomastigophora Flagella filaments (Flagellata) Cilia Fine needle-like filaments Seen in class Ciliata (Infusoria) covering the entire surface of the body ■ Nutrition may be holozoic, saprophytic or homophytic. Digestion takes place in food vacuoles. Primitive digestive organelles, such as cytostome (“cell mouth”), cytopharynx (“cell gullet”) and cytopyge (“cell permanent anus”), seen in class Ciliata. ■ Respiratory organelles are absent. Respiration is by diffusion. ■ Contractile vacuoles situated inside the endoplasm and serve the function of osmoregulation and excretion. Water is always moving into fresh water Amoeba due to osmosis. Osmoregulation If this water is not removed from the cell, the Amoeba in Amoeba would burst. (Fig. 1) Amoeba removes this water by actively pumping (using ATP) water into a contractile vacuole. When the contractile vacuole reaches a certain size it fuses with the cell membrane and release the water outside the cell. Fig. 1. Osmoregulation in Amoeba. ③ Nucleus. It is the most important structure, as it controls the various metabolic processes in cell and regulates reproduction. It is situated inside the endoplasm its structure is often of great help in the differentiation of genera and species. Reproduction may be sexual or asexual. Sexual reproduction may take place by conjugation or by syngamy. Conjugation. In this process, a temporary union of two individuals occurs during which time interchange of nuclear material takes place. Later on, the two individuals separate, each being rejuvenated by the process, as in Ciliata. 5 Syngamy. In this process, sexually differentiated cells, called gametes, unite permanently and a complete fusion of the nuclear material takes place. The resulting product is then known as a zygote, as in Plasmodia. The methods of asexual reproduction among the protozoa are of the following types: Binary fission. In this process, the individual organism divides either longitudinally or transversely into two more or less equal parts. Before division all the structures are duplicated. Budding is a form of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. The new organism remains attached as it grows, separating from the parent organism only when it is mature, leaving behind scar tissue. Since the reproduction is asexual, the newly created organism is a clone and is genetically identical to the parent organism. Schizogony. In this process more than two individuals are produced, as in Plasmodia. The nucleus of the parent cell at first undergoes repeated divisions which are then surrounded by the cytoplasm. When the multiplication is completed, the parasitic body or the schizont ruptures and liberates these daughter individuals which in their turn repeat life cycle. Endodyogeny or Internal budding. It involves an unusual process in which two daughter cells are produced inside a mother cell, which is then consumed by the offspring prior to their separation, as in Toxoplasma. Encystment occurs during unfavourable conditions. The some protozoans possess the property of being transformed from an active (trophozoite) to an inactive stage, losing its power of motility and enclosing itself within a tough wall. The protoplasmic body thus formed is known as a cyst. At this stage, the protozoan loses its power of growth and multiplication. 6 SYSTEMATICS OF PROTOZOANS Diagram #1. 7 Class Rhizopoda or Sarcodina 1. Nutrition is holozoic. 2. Pseudopodia may be in the form of lobopodia, filopodia or reticulopodia. 3. Body is naked or shelled. 4. Asexual reproduction is by binary fission or budding. 5. Encystment also takes place during unfavourable condition. Class Ciliata 1. Body is covered by a protecting membrane called pellicle. 2. Free-living organisms have cilia serving locomotion. In sedentary animals, tentacles serve in food capture (Suctoria). 3. Usually, they have one macronucleus and one micronucleus. Some have more than two nuclei. 4. Some have one or more contractile vacuoles. 5. Reproduction takes place by sexual and asexual methods. Suctorians reproduce by budding. Class Zoomastigophora or Flagellata 1. They are mostly parasites. 2. Some exhibit holozoic or saprobic nutrition. 3. Chromatophores are absent. 4. One or more flagella may be present. Subphylum Sporozoa: Class Telosporea 1. Sporozoite stage is elongated. 2. Locomotor organelles are absent. 3. Asexual reproduction by multiple fission (schizogony). Subphylum Sporozoa: Class Toxoplasmea 1. They are parasites on humans, birds and reptiles. 2. Encystment is seen. 3. Locomotor organelles are absent. 4. Asexual reproduction by binary fission or internal budding (endodyogeny). 8 Class Sarcodina The protozoal parasites belonging
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  • The Fine Structure of Giardia Muris
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