Lecture 1 - Taxonomy, Structure, Physiology Flashcards
Bacteria can be classified as:
1. Frank Pathogens: capable of causing disease in ____ _____ and are always considered a pathogen when _____. Example?
2. Opportunistic Pathogens: capable of causing disease given the ______. Often a ______ and part of the ______ host flora, but is capable
of causing disease in ______ _____ tissues (most
pathogens fall into this group).
3. Non-pathogens: weak or non-pathogenic bacteria can cause disease in hosts with ?
any host, isolated, Yersinia pestis = pathogen that caused the plague.
opportunity, commensal, normal, normally sterile
weakened immune systems.
D=N·V/R
D is inversely proportional to?
–D: disease
–N: Number of organisms
–V: Virulence of the organism
–R: Resistance (innate and adaptive
host immunity) of the host
resistance
Name the three kingdoms/super-kingdoms in which microbes are characterized?
Bacteria, Eukarya, Archaea
Bacterial taxonomy is concerned with:
1. Bacterial _______ schemes are artificial in order to speed up the _______ process, identify bacteria using a limited # of _______.
2. Bacterial nomenclature involves use of a ______ system to assign a _____ and _____, specific conventions for naming.
- Example: Salmonella cholerasuis
3. Bacterial identification is normally based on ______, ________ and _______ “traits”
- other: nucleic acid profile (?). Today, classification is primarily based on?
classification, identification, characteristics, binomial, genus, species, morphological, biochemical, serological, DNA/RNA, DNA protein profiles.
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Cocci
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Diplococci
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Streptococci
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Staphlococci
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Tetrad
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Coccobacilli
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Club-shaped bacilli
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Bacilli with rounded ends
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Bacilli with square ends
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Fusiform bacilli
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Fusiform bacilli
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Vibrios
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Spirilium
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Borrelia
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Treponema
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Leptospira
What is the purpose of the:
1. Flagella
2. Fimbrae
3. Capsule
- helps bacteria move
- help bacteria attach
- outer protective layer
Bacterial spores are formed under what circumstances?
Poor nutrition or unacceptable environment
The terms gram-positive and gram-negative
refer to the _____ of the bacteria after Gram
staining.
• Gram-positive bacteria have a _____
peptidoglycan cell wall and appear
_____/____.
• Gram-negative bacteria have a ____
peptidoglycan wall, but have a _____-____
outer membrane, and appear ____ after Gram
staining.
color, thick, blue/violet, thin, lipid, rich, red
List the steps of a Gram stain procedure
Make a THIN smear from a pure culture on a slide
and heat-fix.
• Cover smear with crystal violet; let stand for 30
sec.-1 min. Rinse.
• Cover smear with Gram’s iodine (mordant); let
stand for same amount of time. Rinse.
• Hold slide at an angle and rinse with alcohol or
alcohol-acetone until blue runs off. Rinse.
• Cover smear with safranin for 30 sec.-1 min.
Rinse, blot dry, and examine under oil immersion
at 100X.
Describe the cell wall of a Gram positive bacteria.
Very thick layer, multiple layers, of peptidoglycans on their cell wall
peptido = peptide, AA
glycan = carbohydrate
Describe the bacterial cell wall of a gram negative cell.
single layer of peptidoglycans
Describe the Peptidoglycan Network,
The amino acids lysine and alanine are linked via a covalent bond. Penicillin binding proteins synthesize peptidoglycans. When the host ingests an antibiotic (Betalactamases which are penicilins, amoxicillin, etc are antibiotics), the antibiotic binds to these proteins, inhibiting the linkage between alanine and lysine.
Disruption of Peptidoglycan in Cell Wall
_________ keeps cells intact. When peptidoglycan is attacked, cell is _______ (_____).
Lysozyme or penicillin is _______ under conditions in which it is used (?).
Peptidoglycan, compromised, blebing, bactericidal, hypertonic, hypotonic conditions aka conditions unfavorable to the cell
Mycolic acids: acid fast bacteria are a family of ?
very long fatty acid side chains.
______ _____ stain (carbofusion) will stain fatty acids
Acid fast
Important
Lipopolysaccharide (LPS) – LPS is also known as ______, and is the predominant lipid in the ____ ____ of the outer membrane of the Gram-______ cell. LPS acts as the prototypical endotoxin because it binds the _____/____/_____ receptor complex, which promotes the secretion of ____-_________ cytokines in many cell types, but especially in _______.
________ response induced is what causes the disease.
endotoxin, outer leaflet, negative, CD14/TLR4/MD2, pro-inflammatory, macrophages, Inflammatory
Flagella is composed of _______ appendages (2-20 um) composed of flagellin ______; allow for ______; “__” antigens can be detected with specific antibodies.
filamentous, monomers, motility, H
Flagella (and pili) may be _______ proteins
glycosylated
Glycocalyx – _____ or _____ layer that is composed of ______ or _______; not necessary for _____, but inhibits _______ and _______ uptake; antigenic when on ____ and “_” antigens can be detected with specific ______.
capsule, slime, carbohydrates, glycoproteins, growth, phagocytosis, antibiotic, cell, K, antibodies
Capsule-like complex of Francisella tularensis
This CLC is thought to be over-expressed outer membrane vesicles,
Pili - _______ appendages (0.5-2.0 um) composed of ___ ______; allow for _______ (____) and specialized ____ ____ allow for transfer of ____ between a donor and a recipient; highly
antigenic and antibodies can be used for ____-_____
filamentous, pilin, monomers, adhesion, fimbriae, sex, pili, DNA, sero-diagnosis
important for attachment, transmitting DNA, transposons, any genetic factors
What are the products of bacterial metabolism? What are these products used for?
Acids, bases, gases, ATP
These products are used to build precursors (ATP is de-phosphorylated, phosphorylates glucose, forms intermediates, etc).
Bacteria can undergo what processes?
fermentation (anaerobic), respiration/oxidation, or photosynthesis
Fermentation process generates _____ and ____.
The oxidation process generates _____.
acids, ATP, NAD
ATP Synthesis - on inner membrane
Electrons go through ____ ______ –> generate ____ –> use ____ to ___.
lipid proteins, ATP, ATP, grow
Fermenters generate _____, oxidizers generate both ____ and _____ but the ____ are ____
Thermophiles = too ____ for most mammals
psychrophiles = too ___
Mainly dealing with mesophiles
acids, acids, bases, acids, weak
high, low
Most bacteria associated with animals grow only in the presence of ____, only _____, either (________), or in ____ and are able to ferment or oxidize _____
– e.g. E. coli, Pasteurella, Staphylococcus –> These bacteria are _______ ______ (fermenters or acid formers), but normally grow better in ___
• Some bacteria are aerobes and only _______ sugars (some acids made but are too ____ to detect)
– e.g. Pseudomonas, Aeromonas, Acinetobacter
• Some bacteria are aerobes, but do not utilize ____ at all
– e.g. Bordetella, Moraxella –> These bacteria utilize _____, ____, or other ______ ______
from ______ _____ or other compounds other than sugars.
air, anaerobically, facultatively, CO2, sugars, facultative anaerobes, air, oxidize, weak, sugars, nitrogen, sulfur, electron acceptors, amino acids
Some bacteria only grow well in the presence of ____ quantities of ____ (3%)
(_______)
– e.g. Campylobacter jejuni
• Some bacteria only grow in air with additional ______ ______ (______)
– e.g. Haemophilus
• Some bacteria only grow in the absence of ____ and only _______ sugars (anaerobic)
– e.g. Bacteroides
low, oxygen, microaerophilic, carbon dioxide, capnophilic, air, ferment
What are the types of Bacteriological Culture Medium?
What are types of media used for isolation and identification?
Two basic types:
• Defined/ simple (e.g. minimal salts)
• Enriched/complex (e.g. nutrient broth)
Examples used for isolation and identification
1. Differential media (e.g. MacConkey agar)
2. Selective media (e.g. Selenite broth)
3. Enriched media (e.g. Blood agar)
4. Transport media (e.g. Stuart’s media)
Summary of Bacterial Physiology
1. Define Metabolism.
2. ATP is synonymous with?
3. Most bacteria are?
4. The by-products of metabolism can be used for?
5. What factors can influence bacterial growth?
- Metabolism is the net result of biochemical activities associated with catabolic and anabolic pathways - leading to growth.
- ATP is synonymous with energy generation - can occur by photosynthesis, respiration or fermentation.
- Most bacteria are chemoheterotrophs.
- • The characterization of by-products associated with metabolism can be used to identify bacteria e.g. “metabolic footprint” (API 20E).
- The incubation conditions of temperature, gas and pH can significantly influence the rate at which bacteria grow. • Culture media can be designed to facilitate growth as well as transport and identification of bacteria.
