bio module 4

pathogen

microorganism that causes disease

live in host, pathogens lvive by takinng nutrition from host, but also cause damage in process

bacteria

belogn to kingdom rpokaryotae
cells smaller than eukaryotic, but can reproduce rapidly

in rightconditions every 20 mintues, so multiply rapidly in host body

preensce can cause disease by damagic cells or releasing waste porducts and toxins that are toxic to host

platns, bacteria can often live in vascular tissues and cause blakcening and death of these tissues

fungi

can also cause varitye of diseases in platns and animals
common cfungal infectiosn where fungus lives in skin of animal and hyphae, form mycelium, grow under skin surface


fungus can send out specialised reproductive hyphae, grow to surface of skin to rleaes spores, cauese redness and irritation

in plants, often lives in vascular tissue, can gain nutrients

hyphae release extracellular enzymes eg cellulases to digest surroidning tissue, causes decay

leaves become mottled in color, curl up and shrivel, before dying

fruit and storage organs, eg tubers(potatoes) will trun black and decay

viruses

invade cells and take over genetic machinery and other organelels of cell
then cause cell to manufacture more opies of virus

host cell eventualyl bursts, relasing many new viruses which infect healthy cells

protoctista

number of diseaess casued by animal like protocists, usually cause harm by entering host clels and feeding on contents as they rgow
malarial parasite plasmodium has immature forms that feed on haemoglobin inside red blood cells

some organisms difficult to classify
phytophthora(blight), classified as fungus for many years
recently moved to kingdom protocista, before being placed in new kingdom(stramenopila)
becez has many features that do not fit with other organisms in previous groups

tubercolosis, bacterial meningitis, ring rot

1 - bacteria mycobacterium tubercolosis and M bovis
ffects many prats of body, killing cells and tissues, lungs often most affected

2 - bacterial meningitis caused by bacteria neisseria meninggitidis or streptococcus pneumonia
infection fo mininges, membrans ethat suround brain and spinal cord
membranse become swollen, may cause dmaage to brain and nerves


3 -bacteriam clavibacter michiganensis susp sepedonicus
ring rot - disease causing ring of decay in vascular tissue of potato tuber, accompanied by laf wilting

HIV/AIDs - human immunodeficiency virus, attakcs cells in immune system and compromises immune response

Influenza, tmv, black sigatoka, blight

1 - viruses from orthomyxovirdae family
attacks respiratiory ssytem and causes muscle pains and headaches

2 - virus of same name, causes mottling and discolorationfo leaves

£ - in anana plants caused by fungus mycosphaerella fijiensis and leaf spots on bana plants and reduces yield


4 - affecs tomatoes andpotatoes, particularly leaves and tubers
caused by protoctistan phytophthora infestans

5 - ringowrm in cattle by fungus trichophyton verrucosum
growth of funguis in skin causes spores to erupt through skin,c ausing rash

athletes foot, malaria

1 - fungus trichophyton rubruma nd grows under skin on feet, betrween toes

2 - protocistan plasmdium falciparium, p vivax, p ovale or p malaerie, parasite in blood that causes headache and fecever and may progress to coma and deth

direct transmission, indirect transmission, transmission, vector

1 - passing pathogen from host to new host, no intermediary
2 - passinkg pathogen from host to new hsot via vector

3 - pasing pathogen from infected indivudal to uninfected individual

4 - organism that carries pathogen from one hst o another
pathogen transmitted, not diasease

phatogen life cycle

by product is to cause harm to host

travel from ones host to another
neter host tissus
reproduce
leaving host tissues

direct physical contact affecitn transimission

eg touching person who infected or touchign contaminate fsurfaces that harbor pathogens

eg hiv, bacterial mnengitis, ringworm, atheletse foot, choplera food posining

risk of this from reduced by better hygienes eg washing hands, keeping surfaces lcean, sterilsiing surgical instruments,c ondoms

faecal oral tarnsmission

usually aeting food or drinking water contamined with pathogen
eg food posinign and cholrea

can be prevented by nto using human sewage as crop fertiliser, treating wastewater and drinking water, throroguly washing fresh food, careful preparation


3 — droplet infection - pathogen carried in tiny water droplets in air
eg tubercolosis, infleunza

can be reduced as r-isk by covering motuh when coughing or sneezing
use tissue and esnure disposed of correcly

4 - transmisison byu spores, resistant stage of pathogen - carired in air or reside on surface eg antrhax,t tenaus - avoid by eawring face mask

ohter factors that affect tranmsission

overcrowding, poor ventilation, poor health, poor diet, homelessnessr

BCG vaccination redudd tubercolosis
immigrants increased it

indirect tranmission

eg plasmodium tthat causes malaria via entering human hoste via bite from female anopheles mosquto

1 - msoquito sucks blood from person infected with malaria
2 - plasmodeium develops from gamets in persons infected blood and mikgrats to salivary glands of mosquito
3 - bites uninfected person
4 - plasmodium from mosquiot migrate into persons liver
5 - plasmodium then migrati to blood
6 - person has malaria

transmission of plant pathogens

can also be spread by direct and indiret

many rpesnet in soil and will infect plants by entering roots - especialyl if have been damaged as reslt of replanting, brrowing anikmals rr movemetn caused nbys torm


many fungi produec spores as mean of reproduction
can be carred in wind - airborne transmissoin
once inside plant, pathogen may infect all vascular tissue

pathogens in leave disributed when leaves shed and carry pathogen back to soil where it can grow and infect another plant

can slo enter fruit and seeds, and distributed wit h seeds so all osfffpsring infected

indirect occurs as result of insect attack s- spores or bacteria attach to burrowing insect eg beetle, attacks infected bplant
when bettle attakcs another plant, pathogen transmitted to uninfected plant
beetle actinv as vector
eg fungus taht causes dutch elm disease carried by beetle scolytus multistriatus

disease and climate

many protoctists, bacteira and fungi can grow and reproduce more rapidly i n warm and moist conditiosn
as global warming alters our climate, tropical pathogens able to survieve mroe easilt in europe
Tropical diseases may becoem more common in europe as result


plants manufacture sugars in photosynthesis and convert sugars to wide variety of compounds eg proteins and oils

represnt rich source of nutrients for many oganisms such as bacteria, fungi, protoctists, cviresuses insects and vertebtrates


all pathogenic or may be vetors but plants do not have immune system but delveodpe whide range of strucutral, chemical nad protein based defensesc - both passive to prevent netry and active when pathogen detected

cellulose cell wall, lignin thickening of cell walsl, waxy cuticles, bark

1 - not only acts as phsycaoil barrier but most plant cell walls contain varity of chmeical defences that can be activedated when detected

2 - lignin(phenolic compound) waterproof and almsot completel indigestible

3 - prevent ater collecting on cell sufaces, since pathoens colect in water and need water to survive, absence of wter passive defence

4 - most bark contains variety of chemical defences that work against pathogenic organisms

stomatal closure, callose, tylose formation

1 - stoamta possible points of entry, stomatal aperture controleld by guard ecells
when pathogenic aorganisms deteced, gaurd cells will close stoamta in that part of p[latn


2 - large polysaccharide that deposited in seivet uebs at endof growing season
deposite daround sieve plattes and blocsk flow in seive tube
can prevent pathogen spreading around plant

3 - tylose, balloon0like swelling or porjectin that fills xylem vesesl
when full formed, plugs vessela nd vessel can no lognger carry water

Blockign xylem vessels prevents spread of phogens through eartwood

tylose - high concentration fo chemeicals eg terpenes that toxic to pathogens

in active xylem, vessels surrounded by living parnchyma cells
as wood ages, parenchyma cells become filled with teprenes
eventually contenst of parenchyma cells brust into ded vessel through pit connected 2two

parenchyma celld eis as cntents enter emtpty space of xylem vessle

chemical defences

pant dtissuec ontain vareity of chemicals with anti pathogenic properties

include terpenoids, phenols, alkaloids and hydrolytic enzymes

some eg terpenes in tyloses and tannins in bark
presnet before infection
however because productoin fo chemicals requires lto of energy, many chemicals not produced until lpant detects infection

active defences

when pathogens attack, specific cehicals in cellw alls can be detected by platn celsl

hecmicals include specific proteins and glycolipids
plant responds by fortifyign defences alreayd present
incresing physical defences and producing defensive chemicals

active defences

cellw walls become thickened and strengthed with additional cellulose
deposition f callose between platn cell walla nd cell membrane near invading pathogen

callose depoistes - polyscacharde polymers that impede cellular peentration at site of incectoin

strengthencs cell walla nd blocks pasodesmata

oxidative bursts that produce highly recative oxygen chemicals capable of damagig cells of invading organisms

increse in production of chemicals

chemicals used in dfeense

terpenoids, phenoils, defensive proteins

1 - range of essential oils that have antibactieral and antifungalprperties

may also create scenet eg m,ethol;s and menthoes produced by int plants

phenols - antibiotic and antifungal proerties

3 - defensins - small cysteine rich proteins that have broad antimicrobial activity
appear to act upon molecules in plasma membrane of pathogens, possibly inhibiting actino of ion transpot channels

hydrolytric enzymes, tannins, alkaloids, necrosis

1 - foudn in spaces between cells
include chitinases(break down chitin found in fungal cell walls)
glucanases(hydrolyse glycoidsid bnds in glucans)
lysozymes(capable of degrading bacterial cell walls)

tannins found in bark nhibit attack by inssecst

compunds bind to salivary rptoeins and difestive enzymes eg trypsin and chymotrypisn, deactivating enzyemes
insecs that ingest high amounts of tnanins do not grow and iwl eventually die
Helps to prevent transmission of pathogens

alkaaloids - nitrogen containinc gompounds eg caffeine, nicotine, cocaine, morphine, solanine
give better taste to inhibit herbivores feeding - acto n vearity of metabolic reactions via inhibiting or activating enzyme action
some inhibit protein synthesis

if platn can reduce grazing by alrge r animasl,w ills ufer less damage that can allow pathogens to enter plant

inflammatoin, mucuous membrane, primary defecnes

1 - swelling and redness of tuissue caused by infection
2 - specialised epitheliam tissue covered by mucus
3 - thoes that prevent pathogens entering body

skin

primary defence
outer layer - epdiermis, consits of lyers of cells
most called keratinocytes
cells predcued by mitsosis at base of epidermis
then migrate out to surface of skin
as migrate, dry out and cytoplasm replaced by protein keratin

keratinisation, 30 days
by time reach sruface, no longer alive
keratiniesd layer of dead cells acts as effecitve barrier to pathogens
eventually dead cells sligh off
much of dust found in houses is dead skin cells

blood clotting and skin repir

skin only protective as it is compelte
abrasions or lacerations damage skin and open body to infection



damage to blodo velslel exposes collagen fibres and releases clotting factors
platelets activated by collagen fibres and change shape, formong temporary platelt plug and also releasing clotting factors
clotting factos activete thrombokinaes(clotting factor x)

withprecesnce of calcium ikosn, able to cnvert protein prothrombin into enzyme thrombin

thrombin catalyses conversion of soluble fibrinogen into insolubel fibrin
whem many fibrin molecuels formed they can polymerise
creating mesh of fibrin fibres that raps that attaches to plateles in plug and traps more red blood celsl and platelts in plug

formign clot that effectively seals wound
scab shrinks as it dries
drawing sides of a cut together

makes temporary cseal, under which skin repaired

1st stage of blood clotting

st stage - deposition of fibrous collagen under scab
stem cells in epidermis then divide by mitsois to form new cells, which migrate to edges of cut and differentaite to form new skin
new blodo vessels grow to supply oxyen and nutrients to new tissues
tissues contract to help draw edeges of cut together so repair can be completed
as new skin cmplete,d scab will be relasd

mucous membranes

oxygen and nutrients in flood must enter blodo
fsurfaces must be thniner and less ewll protected form pathogens

air and food we take in may harbor microorganisms

so ariways, lungs, digestisve system at risk of infection
proteced by mucou smembreanse

epithelial layer contains goblet(mucous secreting) cells
also extra mucus secreting glands uner epithelium

airways, mucus lines passages and trasp any pathogens that may be ina ir

epitheloum also has ciiated cells

cilia tiny, hair-like tthat can move

in coordinated fashion t o waft laeyr of mucus along
move mucus up to top of trache,a where it can enter oesophagus
swallwoed and passes down digestive system

most pathogens in digestise vsystem killed by stomach acidity, pH 1-2
denatures pathogens enzymes
mucous membrans also found in gut, gentical area,s aers, nose

coughing and sneezing

areas proewn to attck also sensitve

respond to irritation that may be cauesd by repesence of microorganism sotor toxins


reflexess incude coughing, sneezing, vomiting
sudden explusion of air will carry microorganisms with it

inflammation

sign tissue is infected is swelling and redness

may also feel hot and painful
presence of microorganisms dtected by spceailised mast cells
relase cell signallign substance called histamein, helps combat infection - vasodilation

make capillary walls more permeable to whtie bloodc ells and some proteins
blood plasma and phagocytic white blood cells leave blood and enter tissue fluid

leads to increased production of tissue fluid, causes swelling(oedema)
excess tissue fluid drained into lumpathic system where lymphocytes stored

can lead to pathogens coming into contact with lymphocytes and initiating specific immune responsses

primary defences

eyes protected by antibodies and enzymes in tear fluid

era canal lined by wax, traps pathogens

female reporudive system proeced by mucus plug in cervix and maintaining relatively acidic conditions in vagina

antigen presenting cell, clonal selection, cytokines, neutrophil, opsonins

1 - cell that isolates antigen from pathogen and places it on plasmam membrane so that it can be recognised by other cells in immune system

2 - selection of specific B or T cell that is specific to antigen

3 - hormone like moecules used in cell signalling to stimulate immune response, fuses with lysosomes to digest foreign matter

4 - priteins that bind to antigen on pathogen and then allow phagocytes to bind

antigens and opsonins - secondary defences

used to combat paogens that have netered body

when pathogen invades body, recognised as foreign by chemical markers on outer membrnae
called antigens

proteins or glycoprotiens intrinsic to plasmam membrnae

antigens specific to organism
own cells have antigens, recognised as our own and do not produce response

opsonins protein molecules that attach to antigens on surface of pathogen, tyep of antibody@

some opsonins not very specifc - so can attach to vrity of pathogenic cells

role of posnin to enhance abilities of phgocytic cells to bind and engulf pathogen

phagocytes

first line of secondary defence phagocytosis - specialised cells in blod and tissue fluid engulf and digest pathogens

neutrophils

most common phagocytes
can recognise by multi lobed nucleus

manufactured in bone marrow
travel in blodo and often squeeze out of blood into tissue fluid

neutrophisl short lived but will be relased in large numebrs as result of infection

contain large numebr of lysosomes
engulf and digest pathogens

neutrophils usually die soon after digesting a few pathogens
dead may collect in area of infection to form pus

neutrophil in phagocytosis

neutrophil binds to opsonin attached to antigen of pathogen
pathogen then engufled by endocytosis, forming phagosome

lysosomes in neutrophil then fuse to phagosome and rlease lytic enzymes into it

after digestion, harmless products can be obosrbed into cell

phagocyte specialisations

receptors on plasma membran that can bind to opsonin or specific antigen

lobed nucleus that allows cell to squeeze through anrrow gaps

well developed cytoskeleton tha thelps cell to change shape to engulf pathogen and move lysosomes and vacuoles around inside cell

many lysosomes containing lysin
many mitochondria to releaes neergy from glucose
lot of ribosomes to synthesis enzymes involved

macrophages

larger cells manufactured in bone marrow
travel in blood as monocytes beofre settlign in body tissues

many found in lymph nodes where they mature into macrophages


dendritic cells(type) found in more periopheral tissues

macrophages play important role in initiatign sepcific responses to invading pathogens
when macrophage engufls pthogen, does nto fully digest it

antigen forms urface of pathogen saved and moved to special protein copmplex on surafceo of cell
cell becomes antigen presenting cell
exposes antigen on its surfae so other cells of immune system can recognise antigen

psecial protein compelx ensures antigen presenting cell not mistaken for foreign cell and attacked by other phagocytes

acvitve immmunity - antigen presentation

antigen presnting cell moves around body where it can come into contact with specific cells that can activate full immune response

T lymophcytes and B lymphocytes

may be only one t cell and one b cell with correct recognition site for atngien

therefore role of antigen prsentinc ells to increase chances that inategen will come in contact with them

specific immune repsonse

acitvation of specific B and T cells called clonal selection
brings into play complex serioesof events that leads to production of antibodies that can produce specific pathogena nd memory cells that will provide long term immunity


whole series of events stimulated acnd coordinated by number of hormone like chemicalos caleldl cytokines
stimulate differentation and activity of macrophages, B cells, T cells

antibodies, B memory cells clonal expenasion, interleukins, plasma cells

1 - specific proteins released by plasama cells that can attach to pathogenic antigens

2 - cells that remina in blodo for long time, providing long term immunitty

3 - incresie in number of cells by mitotic cell division

4 - signalling molecules used to communicate between different white blod cells

5 - derived form B lymphocytes, celsl that manufcature antibodies

T helper cells, T kilelr cells, T memory cells, t regualtor cells

1 - cells that release signalling molecusle to stimulate immune response

2 - cells that tattack and destroy our own body cells that are infeced by pathogen

3 - celsl that remina in blood for long time, prfoviding long term immuniy

4 - cells that are involved with inhibiting or ending immune response

B lymphocytes

develop into 2 types

plasma cells - circulate in blood, manufacturing and relasing antibodies

b memory cells, remin in body for number of years and act as immunogical memory

each B cell carries slightly different DNA code, so antibodies it can produce are slgihtly differnet from those of other b cells

plsama gets cloned form one b cell will maek all identical antibodies

strucutre of plasma celsl specialiesd, will contain numemrous organelles associated with protein synthesis and secreation eg numerous ribsomes, a lot of rough ER, a lot of golgi aparatus and numerious mitochondria

immune response

activation → clonal selection: invading pathogen ahs specific antigens

to trigger immune response, must be detected by T and B lymphocytes that carry specific receptor molecules on palsma membreans

receptor molecules protiens that have shape that is completmentary to shape of antigen

Contact between antigen and lymphocytes can be acheived directly when pathogenic cells enter lymph nodes or via action of antigen presenting cells

Clonal expansino - once correct lymphocytes activatioed, must increase in mumbers to become efecctive
acheived by mitotic cell division

differentation - b and t lymphocytes do not manufacture antibodies directly, once selected, cloens of lymphoctyes develop into range of useful cells

cell signalling

specific immune response - corodinated action of range of cells

to work together effectively, cells need to communicate
cells ignalling

many cell types involved in immune response, so important they can communicate effectively


Communica2ion through release of hormone lkek chemicals - cyutokines

huge range of signalling molecules, each performing difrfent role

to detect signal, target cell must have cell surface receptor of completmentary shape to shape of signalling molecule

examoles of communication using cytokines

macrophages release monokines
some monokines attract neutrophils by chemotaxis - movement of cells towards particular chemical

others stimulate B cells to differentiate and release antibodies


T cells and macrophages release interleukins, can stimulate clonal expansion(proliferation) and differentiaton of B and T cells

many cells can release interferon, inhibits virus replication and sitmulates activity of T killer cells

autoimmune disease

occurs when immune system attacks part of body
normally any B or T cells sepcific to own antigens destroyed during early development of immune system

autominnume disease when antibodies atart to acck own antigens

possible because antigens that are not normalyl exposed, become exposed
causes of autoimmmune uknown, include both genetic and environmental factors

examples of autoimmune dieases

arthiritis - painful inflammation of joint
cause uncertain - starts with antibodies attacking membranes around joint



lupus can affect any part of body, causing swelling mnd pain - may be asociated with antibodies that attack certain protteins in nucleus in cells and affected tissues

agglutinins, antitoxins, opsonins, primary immune response, secondary immune response

1 - antibodies that cause pathogens to stick together
2 - antibodies that render toxins harmless

£ - antibodies that make it esier for phagocytes to engulf pathogen

4- initial response caused by first infection

5 - more rapid and vigoroous respones cauesd by second or subsequent infection by same pathogen

antigens

molecul;es that can stimulate immune respones

almost any molceule couild act as antigen, but usually protiens or glycoprotiens in plasma membrane of pathogen

foreign antigen will be detected by immune system and will stimulate production of antibodies

natiobodies specific to antigen

as antigen specific to roganism, can think of antibody as specific to pathogen

own antigens recognised by immune system and do not usually stimulate any repsonse

antiobdies

immunoglobulins - complex proteins produced by plasma cells in immune system
releasedin response to infection

have region with specific shape that is complentary tothat of particular antigen

immune system must manufcature one type of antibody for ever y antigend etected
antibodies attch to antigens and render them harmless

strucutre of antiobody

molecules Y shaped and have 2 distinct regions
consist of 4 polypeptide chains

how antiobdies work

varity of ways, but most by attaching to antigens on pathogen
3 main groups

opsoninsss

group of antibodies that bind to antigens on ptahogen
then act as binding sites for phagocytic celsltso that these can more easily bind and destroy pathogens

some not very specific and stick to types of molecuels that are not found in host cell eg peptidoglycans found in cell walls of bacteria

other opsonins produced as poart of specific immune response and bind to very sepcific antigen

pathogen may have another use for antigen molecule

eg may be binding site used for attachment to hoste cell

in thsi case, opsonin bound to antigen renderds antigen useless
neutralisation

opsonin assists in phagocytosis, also prevents pathogen entering host cell beefore it can be attacked by phaogcytes

agglutinins

because each antibody molecule has 2 identifcal binding sites able to “crosslink” pathogens by binding antigen on one pathogen with one binding site and then antigen on another pathogen with other binding site

when many antibodies eprform crosslinking they clum ptogteher(agglutinate) opathoeens

2 advantages: agglutinated pathogens physically impeded from carrynig out some functions eg entering host cells, and agglutinated pathogens readily engulfed by phagocytes - particularly effective against viruses

antitoxins

some antibodies bind to molecules that rae released by pathogenic cells
these molecules may be toxic and action of anti toxins renders them harmeless

primary response of antibodies

produced in response to infection
when agent first detected, immune system starts to produce antibodies
unfortunately trakes few days before number of antibodies in blood reises to level that can combat infection successfully - primary immune response

secondary immune response of antibodies

once pathogens dealt with, nbumberof antibodies in blood drops rapidly

antibodies tdo not stay n blood

if body infected 2nd time by same pathogen, antibdoies must be made agian

however as result of specific immue response, will be B memory and T memory cells circulating in blood

thse can recognise specific antigens and immune system can swing into action more quickly

this time, production of antibodies starts sooner and much more rapid

so concentration of antribodies rises sooner and reaches higher concentrtion
known as secondary immne response - suualyl quick enough to prevent any symtpoms being detected by host

epidemic, vaccination

1 - rapid spread of disease through high proportion of population
2 - way of stimlulating immune response so immunity is acheived

vaccination

provides immunity to specific disease s, created by deliberate exposure to antigenic material that has been rendered harmless

atnigenic mateiral usually injected but some cases can be taken orally

immune system treats antigenic material as real disease - as result, immune system activated and manufactures antibodies and memory cells

memory celsl provide long term immunity

antignic material used in vaccines can take varity of forms

forms of antigenic material in fvaccines

whole, live microorganisms- usually not as harmful as those cause real disaes
but must have very similar antigens, so antibodies produced will be effective againt real pathogen

harmless or attenuated version of pathogenic organism

dead pathogen
preparation of antigens from pathogen
toxoid, harmless version of toxin

application of vaccines

herd vaccination - using vaccine to provide immunirt to all or almost all of population at risk

once enough immune - diesease can no longer be spread through propulation and caheive herd uiimmuntiy

to be affective, esential to vaccinate almost all of population
smallpox - necessary to vaccinate 80-85%
at least 95% for measeales

UK - diphtheria, tetanus, whooping cough,, polio, meningitis, MMR
give n to majority of children at appropriate age

ring vaccination

used when new case of disease reported
involves cavccinateing all in mimmediate vicinity of new case

may mean vaccinating people in surrounding hosues or even whole village or town

ring also used in many places in world to control spread of livestock disease

control of epidemics

once disease eradicated or reduced to such low incidence that is unlikely to spread, routine vaccination programme can be relaxed

occured with smallpox

TB vaccinatons also been stopped for most children in UK

however some pathogens can undergo genetic mutation swhich change antigens

memoryc ells produced by vaccinatoin may not recognise new antigens

when occurs, pathogen may be transmistted and incidence of disease increases

infleuneze epidemic

certian pathogens relatively unstable and regularly undergo changes in atntigens

when occurs, epidmmic may rise - threats must be monitroed so new strains of pathgoens can bne identified

enables health auhroties to prepare for impending epidemic by stockpiling suitable vaccines and vaccinating people who are at particular risk from disease

natural immunirty

acheived through normal life processes

artificial - acheived through medical intervintino

immunity actively or pasively

active - acheived when immune activated and manufactures its own antibodies

passive - acheived when antibodies supplied from another source

natural active vs natural passive

1 - provided by antibodies made in immune system as result of infection

peson suffers from disease once and hten immine

2 - occurs when antibodies provided via placent a or breast milk, makes baby immune to disease swto which mother immune

useful in first year of babys life when immune system developing

artificial active immunity

provided by antibodies made in immune sytsem as result of vaccination

person injected with weakened dead or simlar pathogen, or with antigens

activates immune system

artificial passive immuntiy provided by nijection of antiobdies made by anotehr individual

tetanus can also be treated this way when vaccination using toxoid has not worked well

antibiotic, personalised medicine, synthetic biology

1 - chemical which prevents growth of microorganisms, antibiotics can be antibacterial or antifungal

2 - development of designer medicines for individuals

3 - reengineering of biolgoy
could be production of new molecules that mimic natural processes or use of natural molecules to produce new boiological systems that do not exist in nature

source of medicines

currently over 6000 differnte kinds
new druges neede bcause:

new diseas3s eemerging

still many disease for which there are no effective treatments
some antibitoic treatments becoming less effective

accidental discovery

accidentical discovery of antibiotic penicillin by alexander fleming well documented

fungus penicillium releases compounds that kill bacteria

classic example of how science works - scientiist makes observation and sets out to explain what he or she has seen
in this case, work of lferye and chianm, prufiied penicillin that demonstrated potential value of ntibiotics

scientists shuold work togterhe

traditional remedies

many used for centuries

WHO - 80% of wordl population relies on it

india, 7000 different plants used for medicinal propeties
chin, 5000 plants
europe, many modern drugs

morphine - sap from unripe popoy seed heads in neolitichic times

12th century - opium used as anaestheitic

19th century - morphone and opium being used

opiate drugs reduce nervous action in central nervous system, no pain felt

medicinal use fo willow bark to reliev pain - way foudn in 1897 to reduce side effet of stomach bleeding by adding acetyl gropu, eld to aspirin and ibuprofen

obsercvation of wildlife

many ainmals make use of lpmatss with medicineal properties

monkeys baears and other animals rub citrus oils on caots as insecticides and antiseptics to prevent isnect bites and infeciton

birds line their nests with medicinal leaves to protect chicks from blood sucking mites

chimapnzees swllow leaves flolded in particualr ways in order to remove paraisites from digestive tract

further plant research

scientists used traditional plant medicines and animal behavior in starting point in serach for new drugs

aspirin - rsearech into plants used for traditional remedie enables scientsist to isolate active ingredient

molecule can be analysed and similar moelcules mabufcatured

recent decades - discovery of natural drugs has concentrated on tropicalplants

research into disease causing mechanism

pharmaceutical companies conducting research into way that microoranisms cause disease

many make use of receptors on plasma membranes(cell surface membreans) FOR EXAMPLE, hiv VIRUS BINDS TO CD4 AND CCR5 RECEPTOS ON SURFACE OT T HELPER CELLS

IF BINDINW BTWEREN PATHOGENA ND RECPETOR SITE CNA BE BLOCKED, DISEASE CAUSING PATHOGEN CANNOT GAIN ACCESS TO CELL

GLYOCPROTEIN RECEPTOR MOLECULES CAN BE ISOLATED AND SEQUENCED

ONCE AMINO ACID KNON, MOLECULE MODELLING CAN BE USED TO DETERMINE SHAPE OF RECEPTOR

NEXT STEP TO FIND A DRUG THAT MIMICS SHAPE OF RECEPTOR AND COULD EB USED TO BIND TO VIRUS ITSLEF
WHICH WOUL BLOCK VIRUS FROM ENTERING T HELPER CELL

DRUGS THAT INHIBIT ACTION OF CERTAIN ENZYEMS CAN ALSO BE developed

personalised medicine

sequencing technolog3y and molecular modelling have huge potential for furutre medicines

possible to screen genomes of plants or microorganisms to identifiy potential medicinal compouns from dna sequences

hoped that technology an even be taken step further

once technology fully developed, may be possible to sequence egesn from dinividuals with particular cndition and develop specific drugs for ocondition - personalised mecine

synthetic bioplogy

developemento fmnew molecues especially enzymes - that mimic biological systems

anoter way, uesd to diesign and construct nrew devices and systems

devleopment of tomatoes which ocntain pigment anthocyanin
found in blueberries, health benefits - anthocyanins are antioxidants and help against coronary hard disease

antibiotic use and abuse

compounts that prevent grwoth fo fungi or bbacteria
overuse and misuse of antibiotics enabled microorganisms to devlop resistance

mny of curent antibiotics have limited effectivenes as result

some bateria become infamous for multiple resistance to rangeo f antibotics

include clostridium difficile and MRSA

leaf cutter ants farm fungi, feed for glowing larvae

to rpeovent infeciton of fungal gardnes, carry syhmbiotic material which produce antiboitocs

studying bacteria acarried to see if they have poteintal to produce new drugs to treat human bactiera infectins