Microbiology and Immunology

The ability of an organism to resist a particular infection by a pathogen by the action of specialised cells or molecules

Innate and acquired/adaptive

-Present at birth -Cells patrol for infection -Uses simple recognition systems (receptors) that identify common pathogen structures or ‘danger’ -Rapid responses (minutes) -Many cell types involved -Limited capacity

-Not present at birth needs to be ‘acquired’ -Very sophisticated, highly specific pathogen recognition (receptors) -Learnt from invading organisms -Slower response (days) -Highly specialised cells - generates ‘memory’

-To clear/kill potential pathogens in a controlled and efficient process -With limited pathology to the host (self) -After appropriate duration, return to homeostasis -Confer future protection against same pathogen -To check for non-healthy cells

-General health -Infection -Nutrition -Environmental conditions -Microbiome -Pregnancy -Genetics -Exams (stress)

A substance used to stimulate the production of immunity against one or several diseases (without inducing the disease). It is prepared from either the causative agent of a disease, its products, or a synthetic substitute

-The individual -The population: disease declines if majority of population is immune

Complex pathogens, requires understanding of pathogen’s life cycle and immune responses to develop new vaccines, clinical trials are very expensive and time-consuming

-Live -Killed (inactive/attentuated) -Subunits -Nucleic acid Type of response needed/vaccine used is organism dependent

-Abundant and inhabit every conceivable niche on earth -Service many important planetary cycles -Immensely important in health, disease, food and technology -Often used in human health research

Microbial organisms living around us that are not part of our own bodies

The genes harboured by the microbiota

-Important for protection against osmotic and environmental stresses, defines shape, helps with uniform cell division -Target for immune diseases -Target for many antibiotics

-Revolutionary method -Genetic manipulation to make a protein-GFP fusion -Enables live cell, time lapse imaging -Many colour variants, simultaneous visualisation of different proteins

Many fusion proteins malfunction and localisation may be misleading

-Many bacteria and archea have one -Outermost layer of the cell envelope -Crystalline lattice of a single protein -Protective, selective sieve -Often lost in lab strains

-Usually polysaccharide -Sometimes covalently attached to the wall -Important in biofilms -Can be immunogenic -Can help in avoidance of immune responses

-Surface appendages -Protein polymers -Attachment and adhesion -Important in pathogenesis -Immunogenic -Support gene transfer by conjugation -Twitching motility -Huge range of varied classes of appendage -Pili are usually longer than fimbriae

-Incredible rotary motor -Biological nanomachine -Rotation and helical structure generate movement -Chemotaxis gives directionality -Random biased walk

-Triggered by starvation -Incredibly resistant -Heat, solvent, lysozyme etc -Remain dormant for centuries -Germinate when favourable conditions occur

-Communities, often multiple species together -Held together by a matrix -Cells often differentiate

Gram negative bacteria have an extra layer - the outer membrane

An increase in the number of cells