Microbiology Units 1-2 Flashcards
Microbe
Cellular organism and acellular entities too small to see with the naked eye
Generally <1mm in size
Acellular Entities
Nonliving microbes that are notcomposed of cells (e.g. viruses)
Carl Linnaeus (1701-1778)
Creator of binomial nomenclature
Virus
Infectious acellular entity consisting of either DNA or RNA, smallest acellular entities
Antonie van Leeuwenhoek (1632-1723)
Invented the microscope
First person to see a microbe
Father of Microbiology
Francisco Reidi
Disproved spontaneous generation of macroorganisms
Louis Pasteur
-Disproved spontaneous generation of microorganisms
- Developed vaccine from anthrax, rabies, and cholera
- Developed pasteurization
- Helped develop germ theory
Theory of Biogenesis
Life can only come from living organisms
Which two scientists developed germ theory?
Louis Pasteur and Robert Koch
Koch’s Postulates
criteria used to determine which microbe is the source of which disease
John Tyndall
- Demonstrated that Dust Carries pathogens
- Developed Tyndallization sterilization procedure
Ferdinand Cohn
Proved existence of bacterial endospores
Joseph Lister
Developed aseptic surgery techniques
(e.g. hand washing)
Edward Jenner
- Developed smallpox vaccine
- Father of immunology
Phase-Contrast Microscopy
Enhances the visibility of transparent or colorless specimens
Used to examine internal cell structures
Saprophyte
An organism that does not kill other organisms, but eats already dead organisms
Obligate scavengers
Mutualism
A form of symbiosis in which both parties benefit
Commensalism
A form of symbiosis in which one party benefits and the other is neither benefited or harmed
True Pathogen
A pathogen that can cause a disease in a healthy host
Opportunistic Pathogen
A pathogen that can only cause disease in an already compromised host
Refractive Index
A measurement of how greatly a substance slows the velocity of light
Focal Length
Distance between the center of the lens and the focal point
Resolution
Resolving Power
The ability to show detail
Scanning Confocal Microscope
A microscope that uses laser to scan subject at multiple levels
Scanning Electron microscope
Electron microscope that provides 3d image
Fixed Mount
Dried specimen
Hanging Drop Mount
Wet drop using a depression slide
Positive Staining
Negatively charging the surface of a microbe in order to attract basic (alkaline, + charge) dyes
What color is gram-positive?
Gram-Negative?
Positive = Purple
Negative = Pink
What are the Is of culturing microbes?
-Inoculation (Introduction of sample)
-Isolation (Separation of species)
- Incubation (Growth)
- Inspection
- Information Gathering
Synthetic Media
Contains pure organic and inorganic compounds in an exact formula
Complex / Nonsynthetic Media
Contains at least one ingredient that is not chemically definable
Dimitri Ivanoski
Coined the term virus
Discovered tobacco mosaic virus
What is the average size range of viruses?
20-450 nm “Ultramicroscopic”
Bacteriophage
A virus that infects a bacterium
What is the basic structure of a virus
Capsid head (protein head) surrounding a DNA (single- or double-stranded) or RNA (single or double-stranded) core
Matrix proteins
Proteins that connect the viral envelope with the core
Crystalline Structure
The tendency of viruses to be made of long chains of repeating molecules, leading them to resemble crystals
Envelope
Protective covering made of a host cell’s membrane
Mostly found in viruses that target animal cells
Naked virus
A virus/nucleocapsid without an envelope
Capsomers
Identical protein subunits in a virus
Nucleocapsid
Virus structure consisting of a tubular capsid head with nucleic acid core along inside wall
Icosahedral capsid
d20-shaped capsid
Spike Proteins
Proteins that stick out of an an envelope that allows the virus to enter a new host
Poxviruses
Largest and most complex animal viruses
-lacks a typical capsid covering, covering instead of lipids
- dsDNA
- Multiply in cytoplasm
- Targets epidermal cells and subcutaneous connective tissue
Complex Viruses
Viruses that do not form a helical or icosahedral shape
Positive-sense RNA
Negative-sense RNA
ssRNA (single-stranded) genomes ready for immediate translation into proteins
ssRNA genomes that require modification before translation
Polymerase
An enzyme that assists in creating DNA or RNA
Replicase
An enzyme that copies genetic material
Reverse transcriptase
An enzyme that produces DNA from RNA
Six steps for viral multiplication
- Adsorption (Binding to host cell)
- Penetration (Entering host cell)
- Uncoating (Release of nucleic acid)
- Replication/Synthesis
- Assembly
- Release
-viridae
Suffix on family names of viruses
Host Range
Spectrum of cells a virus can infect
3 Means of viral penetration
- Fusion (Envelope fuses with host cell membrane)
- Endocytosis (Entire virus engulf in vesicle
- Injection of nucleic acids
Two forms of virus release
- Budding/Exocytosis (Released via vesicles, creates envelope)
- Lysis (Rupture and death of host, naked and complex viruses)
Cytopathic Effects
Physical damage to a cellI
Inclusion Bodies
Viral particles and proteins that build up inside a cell over time
Damage caused by viral infection
Synctium
A single cell containing multiple nuclei
Damage caused by viral infection
Persistent Infection
Cells harbor the virus for an extended time
Ocogenic
Transformation
(of a virus) having the ability to turn a cell cancerous
The process of making a cell cancerous
Lytic Cycle
Replication of viruses specifically inside bacteria
Virion
A virus outside of a host
Lysogeny
Incorporation of a bacteriophage’s DNA into its host genetic material
(reversible)
Temperate Phage
Prophage
A bacteriophage that undergoes adsorption and penetration but doesn’t replicate
An inactive virus inside a bacterium during lysogeny
Induction
Activation of a prophage inside a bacterium, causing it to resume normal replication processes
Satellite virus/subviral satellite
A virus that is dependent on other viruses and their enzymes to replicate
Viroid
A short piece of RNA with no protein coat
Only discovered in plants
Where do most DNA viruses replicate?
Where do most RNA viruses replicate?
Nucleus
Cytoplasm
Chronic vs. Latent infections
Chronic = slow but active replication
Latent = Inactive
Why are DNA viruses slower to reproduce and mutate?
They use enzymes that check for errors in the genetic code
Zoonosis
A pathogen that can be transmitted from animals to humans
Conjugate Vaccine
A vaccine that contains a piece of a virus instead of the whole things
Pox / Pocks
Skin pustules caused by poxviruses
Smallpox
Exposure means
S/S
2 types
- Spread through inhalation/skin contact
- Fever, malaise, pox, exhaustion, rash (severe s/s = toxemia, shock, clots)
Variola major
Variola Minor
Herpesvirus
Large enveloped icosahedral capsid w/ dsDNA
All have latent stages and can cause recurrent infection
Common opportunists amongst AIDS patients
Which vaccine type provides the strongest immunity
Live, attenuated virus vaccine
3 Types of herpesvirus
- Herpes simplex 1&2 (HSV)
- Herpesvirus 3 / Varicella-zoster virus (VZV)
- Herpesvirus 4 - Epstein-Barr virus (EBV)
HSV-1
HSV-2
(Herpes simplex virus)
Both transmitted via direct exposure to infected body fluids, usually via lesions
Both multiply in sensory neurons and travel to ganglia
HSV-1: cold sores, fever blisters, lesions on oropharynx, enters 5th cranial nerve
HSV-2: Genital lesions, possible oral lesions, possible no lesions, enters lumbrosacral spinal nerve trunk
Herpesvirus 3 / varicella-zoster virus
(common names, transmission)
Chickenpox and shingles
Airborne
Herpesvirus 4 / Epstein-Barr virus (EBV)
(common names, transmission, targeted tissues, s/s)
Infectious mononucleosis / mono / kissing disease
Transmitted via direct oral contact or saliva
Sore throat, high fever, cervical lymphadenopathy (swelling of lymph nodes)
5 hepatitis viruses
(name, nucleic acid type, means of transmission)
- HBV / Hepadnavirus (Enveloped DNA, both ss and ds) Spread via body fluid contact, chronic
- HAV (Naked RNA) Oral-fecal contamination, acute
- HCV / Transfusion hepatitis (Enveloped RNA) spread via blood and sexual contact, acute
- HDV (RNA, defective) transmitted by body fluids, can only infect cells already infected w/ HBV
- HEV (RNA) Fecal-oral contamination
Which hepatitis is the least virulent?
HAV
S/S of HBV
Most show few symptoms and recover
-Minor: Malaise, fever, chills, anorexia, abd discomfort, diarrhea
- Medium: Fever, jaundice (caused by inhibit bile release), rash, arthritis
- Liver cirrhosis and/or necrosis
Human Papilloma Virus (HPV)
Small, nonenveloped dsDNA (100+ strains)
Spread via direct contact or contaminated objects
Chronic warts/verruca, can cause tumors
Common seed warts
Painless, elevated, rough growth often found on fingers
Segmented Virus
Non-segmented Virus
RNA is present in pieces or sections
RNA is one continuous peice
2 types of enveloped segmented ssRNA viruses
- Orthomyxovirus (influenza)
- Bunyavirus
2 Key protein spikes in influenza
Hemagglutinin (H), virulence factor, binds to host
Neuraminidase (N), assists in budding and release
Antigenic Drift
Antigenic Shift
- Constant mutation
- An RNA segment in an influenza virus is replaced by an RNA segment from an influenza virus that infects a different animal
Which is the most virulent influenza?
Influenza A
Characteristics of Bunyaviruses
Transmitted zoonotically, causes periodic epidemics, extremely dangerous
Hantavirus Pulmonary Syndrome (HPS)
American bunyavirus infection
Transmitted by airborne fecal matter of deer and mice
33% mortality rate
8 Enveloped Nonsegmented ssRNA Viruses
(and diseases they cause)
- Paramyxoviruses (red measles/rubeola, mumps)
- Rhabdovirus (rabies)
- Coronavirus (covid, MERS, SARS, common cold)
- Togavirus (rubella/German measles)
- Flavivirus (HCV)
- Arborvirus (West Nile, Dengue, yellow fever, Zika)
- Retrovirus (AIDS)
- Filovirus (Ebola)
Epidemic Parotitis
Mumps
Painful swelling of parotid salivary gland, can cause infertility in males
Found only in humans
2 types of paramyxovirus
- Paramyxovirus (mumps)
- Morbillivirus (red measles/rubeola)
Symptoms of Red measles
Initial: Sore throat, dry cough, headache, conjunctivitis, lymphadenitis, fever
Koplik’s spots: oral lesions
Exanthem - Red, flat, raised, skin lesions
White spots on gums (differentiate from German measles)
Subacute sclerosing panencephalitis (SSPE): degeneration of cerebral cortex, white matter, brain stem
Negeri Bodies
Intracellular inclusions in nervous tissue of rabies victims
Used to diagnose rabies post-mortem
Phases of Rabies
- Prodromal phase - Fever, n/v, headache, fatigue; pain, burning, tingling of wound
- Furious phase - Agitation, delirium, disorientation, seizures, twitching, hydrophobia, hypersalivation
- Dumb Phase - Paralysis, disorientation, stupor
- Coma Phase
- Death
What cells does rabies affect?
Site of wound (1 week)
nerve endings, ganglia, splinal cord, brain
salivary glands
What is the name of the rabies vaccine?
Human Diploid Cell Vaccine
(HDCV)
What does SARS stand for?
Severe Acute Respiratory Disease
What is a more specific name for the Hep C virus?
Flavivirus
Arborviruses
Viruses spread via arthropod vectors
(Mosquitoes, ticks, fleas, gnats)
HRIG
Human Rabies Immune Globulin
Used to flush rabies wound
What condition is (relatively) commonly caused by arboviruses?
Encephalitis
Retroviruses
The virus that causes HIV and AIDS
ssRNA virus
Filovirus
Ebola Virus (non-segmented ssRNA)
Transmitted via body fluid contact from infected humans, fruit bats, primates
Not contagious until symptomatic
Rhinovirus
non-enveloped non-segmented ssRNA virus
Common cold
Poliovirus
Non-enveloped non-segmented ssRNA virus
Begins in GI tract before moving to blood and eventually CNA
Fecal-oral transmission
Reovirus / Rotavirus
Non-enveloped, segmented dsRNA virus
Causes severe diarrhea in infants
What are the two “hemorrhagic fevers” caused by arboviruses?
Dengue Fever
Yellow Fever
What are five s/s of HIV
- Sever pneumonia caused by normally-harmless fungus
- Kaposi Sarcoma (rare vascular cancer)
- Sudden weight loss
- Swollen Lymph Nodes
- General loss of immune function
