5. Microbes and the Immune System Flashcards
What is an Ecosystem?
A biological community of interacting organisms and chemical/environmental factors.
What is a Habitat?
Part of an ecosystem most suited to certain forms of life.
What is a Niche?
A small, specific area of habitat, rapid change can induce ‘feast or famine’ state.
What is species abundance?
The number of organisms.
What is species richness?
Diversity of organisms.
What does all life require?
Energy + Carbon
What is an autotroph?
An organism that can survive directly off of carbon, unlike heterotrophs.
What is a heterotroph?
An organism that has to acquire its carbon from other things like food.
What is Symbiosis?
Interaction between two different organisms living in close physical association.
What is Parasitism?
A form of symbiosis which is beneficial to one, but is disadvantageous to the other.
What is Mutualism?
A form of symbiosis which is beneficial to both organisms involved.
What is Commensalism?
A form of symbiosis between two organisms in which one benefits and the other neither benefits nor is harmed.
What is Quorum Sensing?
Bacteria sensing their population size and coordinating their behaviour accordingly.
What does Quorum Sensing rely on to sense the environment population?
Auto-inducers, they sense when a threshold has been reach and activate cellular processes.
What is a Biofilm?
Microorganisms adhering together to each other and or a surface, contained within an extracellular matrix.
What is Biofouling?
Fouling of underwater structures with micro/macro-organisms.
What is a Microbiome?
Large and mixed population of microorganisms coexisting together under many circumstances.
What is a Pathogen?
An organisms that causes damage and disease to the host. they are a much smaller group of organisms
What is a Primary Pathogen?
Organism causing disease in a healthy organism.
What is Pathogenicity?
The ability of an organism to cause disease.
What is virulence?
The degree or magnitude of capacity to cause disease (fatality/damage rate).
What are Virulence Factors?
Products made by the pathogenic organisms that contribute to overall virulence (e.g. toxins).
What factors can affect susceptibility to infection?
Susceptibility Agent Exposure Dose Virulence
How does mutation effect commensals/pathogens?
It can alter sensitivity to drugs, alter reception recognition of tissue or alter recognition of the host.
How can commensals/pathogens acquire new genetic traits?
Horizontal gene transfer
What is Natural Transformation (Horizontal Gene Transfer)?
Uptake and incorporation of naked DNA.
What is Conjugation (Horizontal Gene Transfer)?
Genetic exchange between bacteria.
What is Transduction (Horizontal Gene Transfer)?
Exchange occurs as consequence of phage predation.
What does the bacteriophage Lytic life-cycle result in?
Results in replication of bacterial genome and destruction of bacteria.
What does the bacteriophage Lysogenic life-cycle result in?
Results in integration of the bacteriophage DNA in the bacterial chromosome.
Name some clinical uses of Antibiotics.
Treatment of infections, Post-surgery recover, required by chemotherapy patients, Use in chronic disease treatment.
Name some causes of Antibiotic Resistance.
Over-prescribing Antibiotics, Patients not finishing treatment, Overuse in livestock, Poor infection control in clinics, Lack of Hygiene and poor sanitation.
What is the initial response to infection?
Activation of local innate immune cells, Increased permeability of local blood vessel, Migration into tissues of more immune cells and plasma proteins.
What is the ‘Danger Model’ of the immune system?
Immune responses are triggered by damage or danger instead of ‘non-self’ antigens.
What are the two types of immunity?
Innate Immunity
Adaptive Immunity
What are the two types of adaptive immunity?
Humoral
Cell-mediated
What is Humoral Adaptive Immunity?
Antibody mediated ‘extracellular attack’
Antibody from B cells
What is Cell-mediated Adaptive Immunity?
Deals with ‘intracellular attack’
Due to T cells
What are the phases of adaptive immune response?
Antigen Recognition Lymphocyte Activation Antigen Elimination Contraction (homeostasis) Memory
What is MHC (Major Histocompatibility Complex)?
The region in the genes responsible for transplantation antigens, which are involved in shielding the body from pathogens.
Where are MHC I found?
On proteins synthesised in the cell.
Where are MHC II found?
Only found on specialised antigen-pressing immune cells such as Macrophages, Dendritic Cells and B cells.
What signals to T cell require to activate?
Antigen present in the context of MHC
Surface molecule co-stimulation
Soluble molecule - cytokines
What are the 5 types of antibodies?
IgA (Dimer) IgD (Monomer) IgE (Monomer) IgG (Monomer) IgM (Pentamer)
Where can Microbiota communities be found?
In the lungs, skin and G-I Tract
Define Vaccination.
A means of producing immunity against pathogens, such as viruses and bacteria, by the introduction of live, killed or altered antigens that stimulate the body to produce antibodies against more dangerous forms.
What are Killed Vaccines?
A vaccine made from killed versions of the organism that is being protected against.
What are Sub-unit vaccines?
Made of toxins that are the pathogenic fragments of bacteria.
What is an Adjuvent?
An agent which acts non-specifically to increase the specific immune response or responses to an antigen.
