BacT Lec 2 Flashcards
What are some extracellular bacterial structures?
Flagella endoflagella/axial filament Pili/fimbriae Capsule Biofilm
What are some intracellular bacterial structures?
Nuclear material
Ribosomes
Inclusion granules
Endospores
Flagella
*Locomotion/Motility
*Number and arrangement can be used for identification
Long, thin structures that extend outward from the surface of the envelope
Monotrichous Flagella
only one flagellum extending from one end of the bacterium
Many flagella extending from one end of the bacterium
Lophotrichous Flagella
Amphitrichous Flagella
One flagellum extending from each of the bacterium
Flagella extending from many different sites on the bacterium
Peritrichous Flagella
Endoflagella/axial filaments
Present in periplasmic space (*inside the bacteria) of spirochettes
*Name two bacteria that move with the use of Endoflagella/axial filaments.
- Treponema pallidum
* Leptospira
Pili/fimbria
Small thread like structures that facilitate *adherence to the host and *contribute to antigenicity. Also use to *attach bacteria to maintain themselves in a favorable environment.
Give an example of bacteria with Pili/fimbria
Bordetella bronchiseptica
*What is conjugation?
Through *sex pili that allow one bacterial cell adhere to another and exchange genetic material.
*What may cause pili loss?
*Mutation in disease-causing bacteria.
*Will pili reestablish if lost?
*Nope
Capsule (thick glycocalix) Polysaccharide (Not present in all bacteria)
Protect against phagocytosis
*protect form drying out
help adhere to a surface where conditions are favorable for growth
Name a bacteria with a capsule.
Bacillus anthracis - Discovered by Sir John McFadyean
Biofilm
Microbes come together in masses cling to surfaces, produces extracellular substances and take in nutrients and biofilm
Mech used to increase virulence
Give an example of a biofilm
Dental Plaque
*Nucleoid
Nuclear region is a mass of DNA; well defined although it is not surrounded by membrane.
*Plasmids
Smaller circular DNA molecules
Ribosomes
Site of protein synthesis. 70S ribosomes composed of *50S and *30S subunits
Inclusion granules
Stores nutrients for times of nutrient shortage.
Endospores
A dormant form that is produced when essential nutrients are depleted in certain bacteria
*What protects the endospore form damage?
*Organic acid called Dipicolinic acid
Name two examples of bacteria that develop endospores?
Clostridium tetani, Bacillus anthracis
What type of bacteria develop endospores?
Low G+C Gram-Postive
*How do bacteria reproduce?
*Binary fission
The time required for the number of bacteria in a culture to double is called?
*generation time (G)
Two common methods of measuring bacterial mass in liquid cultures.
Tubidity
Colony counting
*Tubidity
A measure of total bacteria (live and dead)
*Colony Counting
The number of viable bacteria in a culture
Three requirements for bacterial growth.
Sources of energy “organic” carbon
Metal ions
Optimal temp, pH and need or lack of need for oxygen
Three forms of bacterial metabolism.
Aerobic Respiration - Molecular Oxygen
Anaerobic Respiration - No Molecular Oxygen
Fermentation - Anaerobic or Aerobic - Facultative anaerobic bacteria
4 environmental factors influencing bacterial growth
Temperature
Hydrogen ion
Water activity
Atmosphere
Methods used to limit microbial growth
Refrigeration Freezing Boiling Pasteurization Acidification Increase osmotic pressure Oxygen removal Drying Gamma irradiation Hydrostatic pressure Chemical additives
Sterilization Methods
Moist heat Dry heat Incineration Alcohol flame Gamma irradiation UV light Membrane filtration Cemical
Types of culture media (non selective)
Liquid (broth)
Solid (Agar Media)
Trypticase soy agar with blood
Selective media culture types
Phenylethyl Alcohol Blood Agar
MacConkey Agar
Hektoen Enteric Agar
PEA culture media is for?
Gram-Positive
MacConkey Agar media is for?
Gram-Negative
Bacterial identification methods
Biochemical Antigenic Phage typing Virulence typing Whole-cell fatty acid analysis Genetic analysis Protein analysis Enzyme isotyping
Matrix Assisted Laser Desorption Ionization-Time of Flight-Mass Spectrometry (MALDI-TOF)
Measure a unique molecular fingerprint of an organism. Specifically measures highly abundant proteins that are found in all microorganisms
What are the only bacteria that have the Endoflagella/axial filaments?
Gram-Negative
*What staining is used to detect capsule on bacteria
*Simple Polychrome Methylene Blue
Origin of cross contamination?
Biofilms
What is the structure of bacteria DNA?
Chromosome *Supercoiled
T:F Prokaryotic ribosomes are larger than eukaryotic ribosomes.
False
Prokaryotic ribosomes are smaller than eukaryotic ribosomes.
Bacteria in endospore form are considered?
Extraordinary Resistant: Because they are not readily killed by many antimicrobial treatments
*What are the three location of endospores?
*Center, terminal, sub-terminal
How can the locations of the endospores help?
Location of endospores is used for identification
*What gives endospores their resistant?
*Dipicolinic acid
*Pilli/Fimbriae’s presence on a bacteria greatly increase?
*The bacteria’s ability to attach to the host and cause disease.
What are some environmental stresses that would normally kill bacteria, but endosores can survive?
High Temp High UV Irradiation Desiccation Chemical Damage Enzymatic Destruction
T:F Bacteria endospores are a form of reproduction.
False
It is a survival technique
When do bacteria reproduce?
Under suitable conditions. Proper nutrients, temp, and atmosphere
Two daughter cells grow and divide at the same rate as parent cells is know as?
*Exponential or Logarithmic Growth Rate
Knowing a bacteria’s generation time can help us?
Differentiate between bacteria
Plotting the log of turbidity or number of living cells versus time is referred to at?
The growth curve
What are the three phases of bacterial growth?
Lag Phase (adaptive) Log Phase (exponential) Stationary Phase
Draw the complete bacterial growth phase.
Refer to slide 26 of Lecture 2 BacT.
Which is more accurate turbidity or colony counting?
Colony Counting
How much growth is happening in the Lag Phase?
Very little
What is needed for the Log Phase to be successful?
All the nutrients required, as well as proper temperature, pH and etc.
Which growth phase is it when nutrients becomes depleted?
Stationary Phase
Oxygen required for growth
Aerobic, Microaerophilic (Req O2, High O2 is toxic), & Capnophilic (High CO2)
Oxygen not required or utilized for growth
Obligately Anaerobic (Death by normal atmospheric O2 concentration), Aerotolerant Anaerobe (Poor growth in O2)
Oxygen not required but can be utilized for growth
Facultative Anaerobe
Draw the Food Danger Zone Guidelines
Refer to slide 33 lecture 2 BacT
