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Grow at 0-20C with optimal of 15C
Psychrophiles
Grow at 15-45Cwith optimal of 38C
Mesophiles
Grow at 40-80C with optimal of 60C
Thermophiles
Grow at 65-121C with optimal of 90C
Hypothermophiles
The growth rate is roughly doubled for every ___ degrees celcius?
10C
What is Heat-Shock Response?
When a microorganism experiences a rapid change in temperature and activates batches of stress response genes.
Barophiles or Piezophiles are organisms adapted to grow in _______?
Very High Pressure (up to 1,000atm(110 MPa, or 15,000 psi))
Define: Barotolerant
Organisms that grow well over the range of 1-50 MPa, but their growth rate falls off thereafter
Water activity (aw) is measured by _____?
how much water is available for use.
What is typically measured as the ratio of the solution's vapor pressure relative to that of pure water?
Water activity
Most bacteria require water activity levels __?
> 0.91
Fungi can tolerate water activity levels ____?
> 0.86
Define: Osmolarity
The measure of the number of solute molecules in a solution and is inversely related to aw.
Define: Aquaporins
Membrane-channel proteins that allow water to traverse the membrane much faster than by diffusion.
What do Aquaporins allow?
Help protect the cell from osmotic stress
In addition to moving water, microbes have at least two mechanisms to minimize osmotic stress which are?
Compatible solutes and mechanosensitive channels
Define: Compatible solutes
In hypertonic media, bacteria protect their internal water by synthesizing or importing compatible solutes (e.g., proline or K+)
Define: Mechanosensitive channels
In hypotonic media, pressure-sensitive or mechanosensitive channels can be used to leak solutes out of the cell.
Halophiles require?
High salt concentrations (From 2 to 4 M NaCl (10%-20% NaCl))
Seawater is _____% NaCl?
-3.5%
To achieve a low internal concentration of Na+, halophilic
microbes use special ___ _____ to _____ _____ and replace it with other cations, such as K+
-Ion pumps
-excrete sodium
Define: Sterilization
killing of all living organisms
Define: Disinfection
killing or removal of pathogens from inanimate objects
Define: Antisepsis
killing or removal of pathogens from the surface of living tissues
Define: Sanitation
reducing the microbial population to safe levels
Define: Eutrophication
The sudden infusion of large quantities of a formerly limiting nutrient
Eutrophication can lead to a "Bloom" of _____?
of microbes, which can threaten the existence of competing species
List in order of harshness: Disinfection, Sanitation, Sterilization, Antisepsis
Sterilization, Disinfection, Antisepsis, and Sanitation
Decimal reduction time (D-value) is the ______?
length of time it takes an agent or a condition to kill 90% of the population.
Moist heat is _____effective than dry heat
More
Killing spores and thermophiles usually requires a combination of _____ _____ and _____.
-high pressure
-temperature
Temp and pressure of a Steam autoclave?
121oC at 15 psi for 20 minutes
Two types of Pasteurization?
-LTLT (low temperature/long time)
63oC for 30 minutes
-HTST (high temperature/short time)
72oC for 15 seconds
Pasteurization kills _______ _____the causative agent of Q fever.
Coxiella burnetii
the 5 Physical Agents That Kill Microbes?
-High temperature
-Pasteurization
-Cold
-Filtration
-Irradiation
Micropore filters with pore sizes of _____ can remove microbial cells, but not viruses, from solutions.
0.2 mm
Samples from 1 ml to several liters can be drawn through a membrane filter by _____ or can be forced through it using a ____?
-vacuum
-syringe
T or F: Air can also be sterilized by filtration?
TRUE
Laminar flow biological safety cabinets force air through HEPA filters, which remove > 99.9% of airborne particulate material _____ in size or larger.
0.3 μm
Irradiation is the used of _____?
-Ultraviolet light
-Gamma rays, electron beams, and X-rays
Ultraviolet light pros and cons?
-Has poor penetrating power
-Used only for surface sterilization
-less harmful
Gamma rays, electron beams, and X-rays pros and cons?
-Have high penetrating power
-Used to irradiate foods and other heat-sensitive items
A number of factors influence the efficacy of a given chemical agent, including:
-The presence of organic matter
-The kinds of organisms present
-Corrosiveness
-Stability, odor, and surface tension
Commercial Disinfectants and Antiseptics include?
Ethanol
Iodine (Wescodyne and Betadine)
Chlorine
Ethylene oxide (a gas sterilant)
These damage proteins, lipids, and/or DNA?
Disinfectants and Antiseptics
The hygiene hypothesis is?
since we're being exposed to less pathogens, we are having more auto-immune diseases
Phenolic
Alcohols
Aldehydes
T/F: Bacteria Can Develop Resistance to Disinfectants?
True
What are the ways bacteria can develop resistance to disinfectants?
-Altering the fatty acid synthesis protein normally targeted by triclosan
-Producing membrane-spanning, multidrug efflux pumps
-Forming multispecies biofilms, which offer collaborative protection
What are chemical compounds synthesized by one microbe that kill or inhibit the growth of other microbial species?
Antibiotics
Penicillin is a(n)?
Antibiotic
How does Penicillin work?
Penicillin mimics part of the bacterial cell wall and Prevents cell wall formation and is bactericidal
What do antibiotics target?
-Protein synthesis
-DNA replication
-Cell membranes
What is the use of one microbe to control the growth of another?
Biocontrol
What contains certain microbes that, when ingested, aim to restore balance to intestinal flora?
Probiotics
ex. Lactobacillus and Bifidobacterium
What aims to treat infectious diseases with a virus targeted to the pathogen?
Phage therapy
A possible alternative to antibiotics in the face of rising antibiotic resistance is ____ ____?
Phage Therapy
A ____ is a noncellular particle that must infect a host cell, where it reproduces that it typically subverts the cell's machinery and directs it to produce viral particles.
Virus
The virus particle, or _____, consists of a single nucleic acid (DNA or RNA) contained within a protective protein capsid
Virion
In oceans viruses are really important for ?
Global chemical cycling
In more complex viruses, the protective protein may be called a ?
Head coat
A virion by itself_____?
Does nothing
What is a virus that infects bacteria?
Bacteriophage
What forms a plaque of lysed cells on a lawn of bacteria?
Bacteriophage
An example of a human virus is the _____ virus?
measles
An example of a plant virus is the _______ _______ virus.
Tobacco mosaic virus (TMV)
A virus that integrates its genome into the DNA of a bacterial genome is called a ?
Prophage
Within a human cell, an integrated viral genome is called a?
Provirus
A permanently integrated provirus transmitted via the germ line is called an?
Endogenous virus
We now know that a virus may interconvert among three very different forms:
1.
2.
3.
?
1. Virion, or virus particle
2. Intracellular replication complex
3. Viral genome integrated within host DNA
Define: Virion, or virus particle
An inert particle that does not carry out any metabolism or energy conversion
Define: Intracellular replication complex
Within a host cell, the viral gene products direct the cell's enzymes to assemble progeny virions at "virus factories" called replication complexes.
T/F: Viral genome integrated within host DNA - This may be a permanent condition?
True
Acute viruses (which rapidly kill their hosts) act as _____?
predators or parasites to limit host population density and they also recycle nutrients from their host bodies
Virus-associated mortality may ______ the genetic diversity of host species?
increase
Persistent viruses remain in hosts, where they may ______?
evolve traits that confer positive benefits in a virus-host mutualism.
Marine viruses infect most ____, releasing their minerals in the upper water, where they are available for other phototrophs?
phytoplankton
On a global scale, viruses play an important role in the ____ ____?
carbon balance
Each species of virus infects a particular group of host species, known as its _____ ____?
host range
Which is more common, Chronic viral infections or acute disease?
Chronic viral infections
In contrast to our vast arsenal of antibiotics (effective against bacteria), the number of antiviral drugs remains ____?
Small
West Nile virus is transmitted by mosquitoes infect,______?
many species of birds and mammals.
Chronic infections last ______?
A long time
Acute infections last ____?
A short time
HIV infects _____?
Only humans
Most of our antiviral drugs are all for ____?
Herpes
HIV
Influenza
________
The structure of a virion is to ____?
keeps the viral genome intact, and it enables infection of the appropriate host cell.
The capsid does what?
packages the viral genome and delivers it into the host cell.
T/F: Different viruses make different capsid forms?
True
______ are with 20 identical triangular faces and are super efficient
and have a structure that exhibits rotational symmetry
polyhedral
In some ________ viruses, the capsid is enclosed in an envelope, formed from the cell membrane
icosahedral
The envelope contains _____ ____, which are encoded by the virus.
glycoprotein spikes
between the envelope and capsid, ____ _____ may be found
tegument proteins
Characteristics of Filamentous viruses?
-The capsid consists of a long tube of protein, with the genome coiled inside.
-Vary in length, depending on genome size
-Include bacteriophages as well as animal viruses
-very easy to form (don't need enzymes)
Filamentous viruses show_____symmetry
helical
The pattern of _____ ____ forms a helical tube around the genome, which usually winds helically within the tube.
Capsid Monomers
Tailed Viruses have complex ____ _____?
multipart structures
T4 bacteriophages is also referred to as?
Lunar Lander Model
