Summary
Summary IA (Infection and defenses) Self-study
- Course
- Institution
This is a summary of all the self-study material of IA (Infection and defense), of the veterinary medicine study.
[Show more]
Seller
Follow
ankejesse
Reviews received
Content preview
QuinnChapter 1 - Microbiology, Microbial Pathogens and
Infectious Disease
● Founders of modern microbiology: Louis Pasteur and Robert
Koch
● Pasteur’s germ theory of disease → “germs” lead to disease
● Koch’s postulates → principles for proving that a specific
microorganism caused a particular disease
○ The pathogenic microorganism must be present in
every case of the disease but absent from healthy
animals
○ The suspected microorganism must be isolated and
grown in pure culture
○ The same disease must occur when the isolated
microorganism is injected into healthy susceptible
animals
○ The same microorganisms must be isolated again
from the injected animals which developed disease
● Dmitri Ivanovski → used Chamberland porcelain filters designed to remove bacteria
from drinking water
○ Transmitter tobacco mosaic disease from diseased to healthy plants
● Martinus Beijerinck → Also used Chamberland porcelain filters to demonstrate the
filterability of the agent of tobacco mosaic disease
○ Discovered that the disease could
not be due to a toxin
■ Filtered sap from infected
plants could be used for serial
transmission of the disease
without loss of potency
● Loeffler and Frosch → identified the first
filterable agent from animals
(foot-and-mouth disease)
● Walter Reed → described the yellow fever
virus (filterable agent)
● Bacteriophages: Filterable agents
○ Useful in studies on viral replication and bacterial genetics
● Method of classification of viruses → based on these criteria
○ The type of nucleic acid
○ The symmetry of the virus
○ The presence or absence of an envelope
○ The diameter of the nucleocapsid (helical viruses) or the number of
capsomeres (icosahedral viruses)
1
,Chapter 2 - Subdivisions, Classification and
Morphological Characterization of Infectious
Agents
● Living cells → divided into 2 groups
○ Eukaryotes
○ Prokaryotes
● Organisms in the domains Archaea and Bacteria → prokaryotes
Microscopical Techniques
● Common techniques employed for the examination of microorganisms + the
particular types of microorganisms for which the techniques are appropriate
2
,Pathogenic Microorganisms
● Pathogenic microorganisms: microorganisms that can cause disease in
animals/humans
Bacteria
● Unicellular + small + less complex than eukaryotic cells
● Rigid cell walls containing a peptidoglycan layer, multiply by
binary fission and exhibit considerable morphological
diversity
○ Rods, cocci, helical forms, and branching filaments
● Length: 0.5-5 µm
● Motile bacteria → possess flagella to move around through
liquid
Fungi
● Large group of non-photosynthetic eukaryotes
● Unicellular or multicellular
○ Multicellular fungi → produce moulds (filamentous
microscopic structures)
■ In moulds → cells are cylindrical + attached
end to end forming branched hyphae
○ Unicellular fungi → have a spherical or ovoid shape
+ multiply by budding
● Can secrete potent enzymes that can digest organic matter
● Moisture in environment → favourable
○ Can degrade a wide variety of organic substances
● Small number of fungi → pathogenic
Algae
● Considered plantlike → contain chlorophyll
● Many are free-living in water
● Some grow on surfaces of rocks/other structures in the environment
● Produce pigments which impart distinct coloration to water surfaces
● High water temperatures → growth → production of toxins
Viruses
● Acellular
● Virus particle/virion
○ Nucleic acid → DNA or RNA
○ Enclosed in a protein coat → capsid
○ Some viruses → surrounded by envelopes
● Size: 20-300 nm
● Occur in many shapes
3
, ○ Spherical, brick-shaped, bullet-shaped, elongated, etc.
● Lack the structures + enzymes necessary for metabolism and independent
reproduction → can only multiply withing living cells
● Bacteriophages: viruses that invade bacterial cells
Prions
● Prions: infectious particles that are smaller than viruses and have been implicated in
the neurological diseases of animals
● Distinct from viruses + appear to be devoid of nucleic acid
● Composed of abnormally-folded protein capable of inducing conformational changes
in homologous normal host cell protein
○ Structurally-altered abnormal protein accumulates in + damages long-lived
cells (e.g. neurons)
● Exhibit remarkable resistance to physical and chemical inactivation procedures
Biological Classification and Nomenclature
● Taxonomy: the practice and science of orderly classification of organisms into taxa
○ 3 interrelated parts
■ Identification
■ Nomenclature
■ Classification
○ Important in microbiology because
■ It permits accurate identification of organisms
■ It provides precise names that permit efficiënt communication
■ It groups similar organisms in a way that allows predictions to be
made and hypotheses to be framed with reasonable confidence
regarding members of the same group
○ Phenotypic characteristics used in taxonomy
■ Morphology
■ Metabolism
■ Physiology
■ Cell chemistry
■ Motility
○ Genetic methods used in taxonomy
■ DNA profiling
■ DNA-DNA hybridization
■ Multilocus sequence typing (MLST)
■ Percentage of guanine + cytosine in an organism’s DNA (GC ratio)
● Microorganisms → named according to the binomial system → in italics
○ 2 parts → capitalized generic name + specific epithet
○ e.g. Bacillus anthracis
■ Bacillus → generic name
■ anthracis → specific name
● Taxonomy of viruses
○ It is considered unlikely that viruses evolved from a single original protovirus
→ the highest level recognized is ‘order’
4
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller ankejesse. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.33. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75057 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now