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There are two types of host: 1. Definitive, and 2. Intermediate host.
There are two types of host:
1. Definitive, and
2. Intermediate host.
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In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist guest (symbiont). The guest is typically provided with nourishment and shelter.
In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist guest (symbiont). The guest is typically provided with nourishment and shelter.
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Protozoa are divided into four major groups based on the structure and the part involved in the locomotion: 1. Mastigophora or Flagellated protozoans: They are parasites or free-living. They have flagella for locomotion Their body is covered by a cuticle or pellicle Freshwater forms have a contractiRead more
Protozoa are divided into four major groups based on the structure and the part involved in the locomotion:
1. Mastigophora or Flagellated protozoans:
They are parasites or free-living.
They have flagella for locomotion
Their body is covered by a cuticle or pellicle
Freshwater forms have a contractile vacuole
Reproduction is by binary fission (longitudinal division)
Examples: Trypanosoma, Trichomonas, Giardia, Leishmania, etc.2. Sarcodina or Amoeboids:
They live in the freshwater, sea or moist soil.
The movement is by pseudopodia. They capture their prey by pseudopodia
There is no definite shape and pellicle is absent
The contractile vacuole is present in the amoeboids living in freshwater
Reproduction is by binary fission and cyst formation
Examples: Amoeba, Entamoeba, etc.3. Sporozoa or Sporozoans:
They are endoparasitic.
They don’t have any specialised organ for locomotion
The pellicle is present, which has subpellicular microtubules, that help in movement
Reproduction is by sporozoite formation
Examples: Plasmodium, Myxidium, Nosema, Globidium, etc.4. Ciliophora or Ciliated protozoans:
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They are aquatic and move actively with the help of thousands of cilia.
They have fixed shape due to covering of pellicle
They may have tentacles, e.g. in the sub-class Suctoria
Contractile vacuoles are present
Some species have an organ for defence called trichocysts
They move with the help of cilia and the movement of cilia also helps in taking food inside the gullet
They reproduce by transverse division and also form cysts
Examples: Paramecium, Vorticella, Balantidium, etc.
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A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host. There are three main classes of parasites that can cause disease in humans: protozoa, helminths, and ectoparasites.
A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host. There are three main classes of parasites that can cause disease in humans: protozoa, helminths, and ectoparasites.
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Fimbriae and flagella are both filamentous proteinaceous structures found on the surface of some bacterial cells, but they have different functions and structures. Fimbriae are bristle-like short fibers that occur on the surface of some Gram-positive and Gram-negative bacteria. Their main function iRead more
Fimbriae and flagella are both filamentous proteinaceous structures found on the surface of some bacterial cells, but they have different functions and structures. Fimbriae are bristle-like short fibers that occur on the surface of some Gram-positive and Gram-negative bacteria. Their main function is surface attachment, which enables the bacterial cell to stick to the surface of host cells. They also help in the formation of pellicles or biofilms.
Flagella, on the other hand, are long whip-like filamentous structures present in some bacteria. The most important function of flagella is to assist in locomotion. Flagella can also act as a sensory organ to detect temperature and the presence of certain chemicals in the external environment of the cell.
In summary, fimbriae are used for attachment while flagella are used for movement.
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Non-capsulated bacteria are bacteria that lack a capsule. A capsule is a protective outer covering on certain gram-negative and gram-positive bacteria that increases virulence. The capsule acts to prevent desiccation and phagocytosis. Bacteria without a capsule, or non-capsulated bacteria, include NRead more
Non-capsulated bacteria are bacteria that lack a capsule. A capsule is a protective outer covering on certain gram-negative and gram-positive bacteria that increases virulence. The capsule acts to prevent desiccation and phagocytosis. Bacteria without a capsule, or non-capsulated bacteria, include Neisseria, Corynebacterium, Salmonella, Shigella, Vibrio, Proteus, Pseudomonas.
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There are several methods that can be used to identify bacteria. Some of the most common methods include: 1. Microscopy: Bacteria can be observed under a microscope, where their shape, size, and arrangement can provide clues to their identity. 2. Culture: Bacteria can be grown in a laboratory on nutRead more
There are several methods that can be used to identify bacteria. Some of the most common methods include:
1. Microscopy: Bacteria can be observed under a microscope, where their shape, size, and arrangement can provide clues to their identity.
2. Culture: Bacteria can be grown in a laboratory on nutrient media, where their growth characteristics, such as colony morphology and color, can provide information about their identity.
3. Biochemical tests: Various biochemical tests can be performed on bacterial isolates to determine their metabolic capabilities and enzymatic activities, which can help identify the bacteria.
4. Serological tests: Serological tests can be used to detect specific antibodies or antigens associated with particular bacterial species.
5. Molecular methods: Molecular methods such as PCR and DNA sequencing can be used to identify bacteria based on their genetic material.
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The capsule is found most commonly among gram-negative bacteria: Escherichia coli (in some strains) Neisseria meningitidis Klebsiella pneumoniae Haemophilus influenzae Pseudomonas aeruginosa Salmonella However, some gram-positive bacteria may also have a capsule: Bacillus megaterium for example, synRead more
The capsule is found most commonly among gram-negative bacteria:
Escherichia coli (in some strains)
Neisseria meningitidis
Klebsiella pneumoniae
Haemophilus influenzae
Pseudomonas aeruginosa
Salmonella
However, some gram-positive bacteria may also have a capsule:Bacillus megaterium for example, synthesizes a capsule composed of polypeptide and polysaccharides.
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Bacillus anthracis
Streptococcus pyogenes synthesizes a hyaluronic acid capsule.
Streptococcus pneumoniae has at least 91 different capsular serotypes. These serotypes are the basis for the pneumococcal vaccines.
Streptococcus agalactiae produces a polysaccharide capsule of nine antigenic types that all contain sialic acid (Ia, Ib, II, III, IV, V, VI, VII, VIII).
Staphylococcus epidermidis
Staphylococcus aureus
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It is the differential staining techniques which was first developed by Ziehl and later on modified by Neelsen. So this method is also called Ziehl-Neelsen staining techniques. Neelsen in 1883 used Ziehl’s carbol-fuchsin and heat then decolorized with an acid alcohol, and counter stained with methylRead more
It is the differential staining techniques which was first developed by Ziehl and later on modified by Neelsen. So this method is also called Ziehl-Neelsen staining techniques. Neelsen in 1883 used Ziehl’s carbol-fuchsin and heat then decolorized with an acid alcohol, and counter stained with methylene blue. Thus Ziehl-Neelsen staining techniques was developed.
The main aim of this staining is to differentiate bacteria into acid fast group and non-acid fast groups.
This method is used for those microorganisms which are not staining by simple or Gram staining method, particularly the member of genus Mycobacterium, are resistant and can only be visualized by acid-fast staining.
Principle of Acid-Fast Stain
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When the smear is stained with carbol fuchsin, it solubilizes the lipoidal material present in the Mycobacterial cell wall but by the application of heat, carbol fuchsin further penetrates through lipoidal wall and enters into cytoplasm. Then after all cell appears red. Then the smear is decolorized with decolorizing agent (3% HCL in 95% alcohol) but the acid fast cells are resistant due to the presence of large amount of lipoidal material in their cell wall which prevents the penetration of decolorizing solution. The non-acid fast organism lack the lipoidal material in their cell wall due to which they are easily decolorized, leaving the cells colorless. Then the smear is stained with counterstain, methylene blue. Only decolorized cells absorb the counter stain and take its color and appears blue while acid-fast cells retain the red color.
There are three types of human parasites: 1. Protozoa: Protozoa are single-celled organisms that can multiply in humans. These parasites can spread through contaminated food and water, person-to-person contact, and insect bites. Protozoa include Plasmodium malariae, which causes malaria infection, aRead more
There are three types of human parasites:
1. Protozoa: Protozoa are single-celled organisms that can multiply in humans. These parasites can spread through contaminated food and water, person-to-person contact, and insect bites. Protozoa include Plasmodium malariae, which causes malaria infection, and Cryptosporidium, which is ingestible.
2. Helminths: Helminths are parasitic worms that often root in a person’s digestive tract. These parasites cannot multiply or divide within a human body and eventually pass through a person’s stool. These include Ascaris lumbricoidesTrusted Source and hookwormTrusted Source parasites.
3. Ectoparasites: Ectoparasites are small organisms that live on the outside of the body. These include ticks, fleas, and lice.
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