Horizontal Gene Transfer & Microbial Interactions Flashcards

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1
Q

segments of DNA that encode enzymes and other proteins that mediate the movement of DNA within genomes (intracellular mobility) or between cells (intercellular mobility)

A

Mobile genetic elements (MGEs)

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2
Q

genes common to all individuals of a species

A

Core genome

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3
Q

genes sporadically present in a species that may also be shared with other species

A

Pan genome

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4
Q

2 requirements of transformation

A

Competence
Host homologous recombination system

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5
Q

Does this describe generalized or specialized transduction:
Occasionally during lysis bacteriophage make a mistake and package host DNA in the capsid instead of bacteriophage DNA
This DNA is then carried passively with the phage head and injected into the next host cell it contacts
Each fragment of host DNA has an equal probability of being packaged

A

Generalized

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6
Q

Does this describe generalized or specialized transduction:
Generally involves close association between a phage and its host genome in the form of lysogeny
Chromosomal genes closely linked to the prophage may be erroneously packaged with the phage
These genes may become permanent residents within the phage genome leading to lysogenic converting phage

A

Specialized

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7
Q

Does this describe generalized or specialized transduction:
Homologous recombination is required to integrate the DNA into the recipient genome

A

Generalized

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8
Q

Does this describe generalized or specialized transduction:
Homologous recombination is not required because the DNA is part of the phage

A

Specialized

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9
Q

Broadest host range form of gene transfer

A

Conjugation

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10
Q

Does conjugation require recombination?

A

Generally does not

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11
Q

the most important mechanism of gene transfer in nature

A

Conjugation

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12
Q

Genetic elements that are replicated and inherited independently from the bacterial chromosome
Encode a negative regulator circuit (cop) that keeps the copy number within prescribed limits differentiating them from phage
Frequently carry genes for antibiotic resistance and virulence factors

A

Plasmids

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13
Q

non-replicating genetic elements capable of “hopping” or transposing from one position on the genome to another
Encode an enzyme called transposase that recognizes the ends, cuts them from their initial location and catalyze their movement to a new location

A

Transposons

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14
Q

clusters of related genes variably present in strains of the same species and associated with bacteriophage-like genes and properties
Have GC contents suggestive of foreign acquisition

A

Genomic (pathogenicity) islands

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15
Q

F plasmid sometimes integrates into the bacterial chromosome by homologous recombination, generating this type of cell

A

Hfr cell

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16
Q

An incorrect excision of the integrated F plasmid brings along a portion of the chromosome, generating this type of cell

A

F’

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17
Q

mobile genetic elements that combine features of bacteriophage, plasmids, and transposons and may include genomic islands

A

Integrative conjugative elements (ICE)

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18
Q

Colonizers are predominately

A

Anaerobic
Particularly in the GI

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19
Q

Microbial density and diversity increases or decreases from proximal to distal gut?

A

Increases

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20
Q

Microbial density and diversity increases or decreases from gut surface to lumen?

A

Increases

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21
Q

Simple sugars are taken up or digest here

A

Small intestine

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22
Q

Complex “indigestible” carbohydrates (fiber) are fermented by bacteria here

A

Large intestine

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23
Q

Does the small intestine have more or less sIgA than the colon?

A

More

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24
Q

Intestinal bacteria can synthesize these 2 vitamins

A

K and B vitamins

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25
Q

Intestinal bacteria can synthesize short chain fatty acids (SCFA), particularly this

A

Butyrate

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26
Q

Capsular polysaccharides and SCFAs stimulate production of these two things

A

IL-10 and Tregs

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27
Q

Segmented filamentous bacteria stimulate this type of T cells important for mucosal immunity to pathogens

A

Th17

28
Q

These are 3 benefits of production of this:
Stimulation of Treg cells to reduce inflammation
Drives colonocyte metabolism to consume oxygen and reduce nitrate production to maintain hypoxia
Stimulation of production of beta defensins

A

Butyrate (SCFA)

29
Q

In a normal symbiotic situation, the gut is kept hypoxic by this

A

Beta oxidation

30
Q

In dysbiosis after treatment with antibiotics, colonocyte metabolism changes to this

A

Glycolysis
Allows the overgrowth of pathogenic bacteria

31
Q

Is gum disease or dental infections associated with this:
Higher risk of cardiovascular disease, complications of diabetes, preterm birth

A

Gum disease

32
Q

Is gum disease or dental infections associated with this:
Pneumonia

A

Dental infections

33
Q

Normal vaginal ecology is predominately this species

A

Lactobacillus

34
Q

Lactobacillus-free ecology is type #?

A

Type IV
Is associated with higher vaginal pH, higher incidence of vaginosis (Nugent score) and higher incidence of preterm labor, less effective HIV biocide prevention

35
Q

Products with live bacterial cultures meant to provide benefit while growing in the host (traditional yogurts and fermented dairy products, pills, cosmetics, mattresses, etc.)
Generally regarded as safe (GRAS)
Predominately Lactobacillus and Bifidobacteria species
The majority of studies have failed to show benefit in healthy individuals and they are not recommended by the FDA for treatment of any medical condition

A

Probiotics

36
Q

Probiotics are predominately these 2 species

A

Lactobacillus and Bifidobacteria

37
Q

Essentially probiotics FDA approved for treatment of specific diseases
Contains live organisms, such as bacteria
Is applicable to the prevention, treatment, or cure of a disease or condition of human beings
Is not a vaccine
May include gut organisms that are not GRAS
May include microorganisms genetically modified to deliver a bioactive compound
None currently available

A

Live biotherapeutic products (LBPs)

38
Q

Microbial food, generally carbohydrates, indigestible by the host
Stimulate growth of beneficial microbes that are already present
Are unregulated nutritional supplements
Dietary fiber positively influences gut function, immune function, glucose tolerance, metabolic regulation, and reduces the incidence of colon cancer

A

Prebiotics

39
Q

Bacterial or host metabolites that facilitate establishment of a beneficial microbiome, e.g. SCFA
Interference with microbial production of trimethylamine-N-oxide (TMAO) which is associated with cardiovascular disease

A

Postbiotics

40
Q

Fecal microbiome transplantation (FMT) is approved for treatment of these infections

A

C. diff

41
Q

Infections with ________ bacteria are usually acute and severe but relatively brief

A

Encapsulated

42
Q

Infections with _______ bacteria usually cause infections that are insidious and chronic

A

Intracellular

43
Q

This microbial component inhibits complement binding

A

Capsule

44
Q

Exotoxins or endotoxins:
Both gram negative and positive

A

Exotoxins

45
Q

Exotoxins or endotoxins:
Can be secreted

A

Exotoxins

46
Q

Exotoxins or endotoxins:
Typically encoded on phages and plasmids

A

Exotoxins

47
Q

Exotoxins or endotoxins:
Most are heat labile

A

Exotoxins

48
Q

Exotoxins or endotoxins:
Only gram negative

A

Endotoxins

49
Q

Exotoxins or endotoxins:
Part of the outer membrane

A

Gram negative

50
Q

Exotoxins or endotoxins:
Encoded on the chromosome

A

Endotoxins

51
Q

Exotoxins or endotoxins:
Heat stable

A

Endotoxins

52
Q

Hemolysins and cytolysins are _____ forming proteins

A

Pore
Protein or peptide monomers that multimerize in the cell membrane leading to pore formation

53
Q

Part of A-B toxin that binds the toxin molecule to a specific receptor

A

B (heavy) chain

54
Q

Part of A-B toxin that enters the host cell and enzymatically interferes with an essential host function like protein synthesis, signal transduction, or interference with neurotransmitters

A

A (light) or Active chain

55
Q

Many A-B toxins are on these

A

Mobile genetic elements

56
Q

A nanostructure for delivering bacterial toxins to a host cytoplasm
Related to flagellar systems
Delivered proteins are referred to as effectors and may have various effects including promotion of uptake, interference with signal transduction, and induction or inhibition of apoptosis
So far detected only in gram negative bacteria

A

Type III Secretion systems

57
Q

Type III Secretion systems have only been detected in this type of bacteria

A

Gram negative

58
Q

Type III Secretion systems are related to these systems

A

Flagellar

59
Q

Crosslinks the MHC and TCR without antigen processing
Activates 2-20% of all T cells
Cause a variety of symptoms including shock and vomiting
Many bacterial are phage-encoded (lysogenic conversion)

A

Superantigens

60
Q

Many bacterial superantigens are encoded in this

A

Phage-encoded (lysogenic conversion)

61
Q

Superantigens crosslink the MHC and TCR without this

A

Without antigen processing

62
Q

Quorum sensing involves this type of feedback loop

A

Positive

63
Q

Regulating the switch from invasion to toxin production
Biphasic growth: Attachment and immune evasion –> Toxin production and attack
Secreted molecule (autoinducer) inducing a “feed-forward” loop leading to a rapid peak of induction

A

Quorum sensing

64
Q

Homoserine lactones are examples of autoinducers in gram _______

A

Negatives

65
Q

Peptides are examples of autoinducers in gram _______

A

Positives