Week 11 Sem 1 2014 Flashcards
Apicomplexa = parasitic protists
Characterised by specialised organelles (rhoptry,micronemes,apicoplast
Alot of diseases caused by apicomplexan organisms eg toxoplasmosis
Malaria
Parasitic diseases
Caused by
Helminths (metazoans)
Protozoans
Ectoparasites
Parasites
All r EUKARYOTES (not archaea/ bac)
Parasite= broadly: organism that lives upon/within another at the expense of the host
Parasitic disease due to= helminths
Protozoans
Ectoparasites
Helminths (worms)
Nematodes
Platyhelminths: cestodes n trematodes
There is a worm that can attack for every organ
Life cycle :
Direct (go out n then go in eg via faecal-oral/skin penetration) vs indirect (need intermediate host)
Filarisis /filariasis
Parasitic disease caused by round worms( nematodes)
Can b lymphatic filarisis (=elephantitis)
Or subcutaneous filarisis
Protzoa
Single celled eukaryotes
Can infect in MANY places in body eg blood (malaria), intestine (giardia), skin (leishmania)
Kinetoplastid
Single celled- Flagellated protozoan
Characterised by kinetoplast (extra dna not in nucleus)
2 main gps:
Trypanosomes (american tryp… & african tryp…)
Leishmania
American trypanosomiasis= disease
Aka chagas disease
Due to the american trypanosome ie
Trypanosoma cruzi
Zoonosis of humans
Transmission via triatomine bug(“kissing bug”)
Deaths Mainly in central n sth america
2 phases of disease:
Acute (fever, swellin of eyes, vomitin)
Chronic( infection can remain dormant for many yrs- can get heart /intestinal problems)
African Trypanosomiasis= disease
Aka african sleepin sickness
Due to trypanosoma brucei (has antigenic variation
Usually in subsaharan africa
Usually by tsete fly bite
2 stages to disease 1) fever headache
2) confusion numbness trouble sleepin
Can die within few wks
Can test wit lumbar puncture
Leishmaniasis= disease
Due to leishmania spp.
(Btw spp = abreivation for multiple species)
Geographically diverse
Spread by sandfly bite
Disease presented in 3 ways: visceral/cutaneous/mucosal
Toxoplasmosis
Due to toxoplasma gondii
Mostly passed to human by CAT faeces /uncooked meat/contaminated water
Esp dangerous for pregnant ppl who get it first time in 1st trimester - kid will get severe abnormalities
Malaria
Plasmodium is no. 1 most deadly parasite
About 1-2 million ppl die each yr -most r kids under 5
Notes for parasitic diseases stuff
No vaccine for any human parasite
Prevention is key
Most occur in tropical/subtropical regions of world eg africa
Giardiasis
Disease due to protozoa (giardia lamblia)
Diarrhoeal disease
One of the most common waterborne disease
Simple life cycle
Viral pathogenesis
Process where viral infection leads to disease
Viraemia
Medical condition where viruses enter bloodstream n hav access to rest of body
Primary = initial spread of virus in blood from first site of infection
Secondary= primary viraemia + infection of other tissues via bloodstream
Tissue tropism
Wen virus prefer a particular tissue to infect n replicate
Antiviral agents
‘Like antibiotics ecept biotics KILL BAC where as here we STOP DEVELOPMENT of VIRUS
Stuff that inhibit development of viruses
Eg nucleoside analogues
Interferons
Inhibition of coatin wit adamantanamin amantadine)
Humoral immunity
Involves antibodies in body fluids + b lymphocytes
No direct contact bw immune cells n pathogen
Cell-mediated immunity
Direct contact bw immune cells n pathogen
Involves t lymphocytes n macrophages
Leucocyte
Wbc
Lymphocyte
3 Types of wbc:
NK cells
T cells
B cells
Haemagglutinin
Antigens
Binds virus to cells with sialic acid on membrane n
Allows viral genome to enter via fusion of host membrane with viral membrane
glycoprotein on surface of virus
Neuraminidase
Glycoprotein on surface of virus
Enzymes that hydrolyse sialic acid residues bw host cells and progeny virus
Allows virus to leave host after it infected it
Antigenic shift
Big changes - almost new strain of virus
Only Wen 2 viruses infect same cell
Get recombo of dna/rna.
Antigen
Non-self markers entering a person
Horizontal transmission
Transmission of pathogens bw people in community
Vertical transmission
From father or mother to foetus/child
Eg breast milk, saliva etc
Epidemic
Rapid rise in incidence above the normal level
Eg flu season, influenza A (H1N1)
Outbreak
Sudden or unexpected occurence of disease in a particular part of population
Eg meningococcal
Endemic
Disease there all the time at a certain level
Eg cholera
Pandemic
Epidemic gone global
Eg influenza A
Hyphae
Long fliamentous structure in fungi
Mycelium
Mass of hyphae
In fungi
Budding
Asexual replication/ reproduction in yeast
Pseudomycelium
Cells cling togez in chajns resembling small tru mycelia
Fake mycelia
Ergosterol
In cell membrane of fungi
Mycotoxin
A fungal toxin
Toxic Secondary metabolite
Moulds excrete mycotoxins
Produced by fungi growing in foods eg grains, nuts or fruits
Mycotoxicoses
Poisoning due to mycotoxins
Can be acute or chronic
Stachybotrys
Type of mold (that releases mycotoxins)
Grow on wallpaper, paper, material in buildings
Cause dermatitis, seizures etc
Mycosis
Pl. mycoses
Fungal infection of animals + humans
Cutaneous fungal disease
Fungal infection in epidermis, hair, dead skin, nails
Eg tinea (aka ringworm)
Dermatomycoses
Fungal infection of skin
Dermatophytes= group of fungi commonly causing skin disease
Subcutaneous fungal infection
Fungal infection to dermis, subcutaneous,tissues,muscle
Eg sporotrichosis (aka rose gardener’s disease)
Candida
Type of yeast
Candida albicans is part of normal flora, causes oral/vaginal thrush
Candidiasis =thrush= fungal/yeast infection by candida
Opportunistic mycoses
Aspergillosis
Name given to wide range of diseases caused by Aspergillus (genus of fungi )
3 types of pulmonary aspergillosis:
- Allergic
- Agressive tissue invasion (to lungs n other organs)
- Fungus ball
Polyenes
‘Anitbiotics’/ antimicrobial polyene compounds that target fungi
Destroy membrane structure
Eg amphotericin B
Nystatin
Azole
Antifungal
Disrupt ergosterol biosynthesis
Inhibit 14 alpha-demethylase
Fungistatic
Eg fluconazole
Intraconazole
Beware: effects on hepatic n intestinal CYP450 enzymes n P-glycoprotein transporter
Co-trimoxazole
Antibiotic for bacteria, fungal and protozoal infections?
Influenza
Viral infection of lungs
Orthomyxovirus
Family of RNA viruses
Influenza A and B cause influenza
Influenza A and B has:
8 segments of RNa
Enveloped
Antigens on protein coat made of glycoprotein
Influenza A,B,C
Influenza A- responsible for regular outbreaks, can cause pandemic, epidemic, flu season
Affect humans n birds n other animals
Influenza B- sporadic outbreaks of illness
Humans only
Influenza C- minor resp illness
Milder than A n B
Influenza A virus
In humans: 3 subtypes of H n 2 subtypes of N r influenza viruses
In animals n birds: 16 subtypes of H n 9 subtypes of N
Antigenic drift
Influenza A B n C all undergo this
Small genetic changes ( eg pnt mutation) causing tiny changes in H or N proteins
Antigenic shift
Sudden appearance of different H subtype
Eg wen 1 virus from bird n 1 from human both infect pig - inside pig rearrangement of genetic stuff = WE’RE ALL DEAD
May or may not have change in S subtype too
New surface antigens = no recognition by immune response
= can lead to pandemic
Swine influenza A (h1n1)
Incubation period 1-2 days
Virus can survive on hard, non porous surfaces for 24-48 hrs N Cloth, paper, tissues for 8-12 hrs N On hands for 5 mins
Haemopoietic ‘niche’ cells
Mesenchymal cells
Nerve cells
Osteoblasts
Self renewal
HSC (haematopoietic stem cells) r self renewing: wen they proliferate, at least some of the daughter cells remain as HSC, so pool of stem cells doesnt become depleted
Potency
Capacity to differentiate into specialised cell types
Totipotent stem cells
Can produce all cell types
Only zygote+ early dividing blastomeres( up until 8 cell stage ie 2 and a bit days) + extraembryonic tissue (eg part of placenta) r truly totipotent
Pluripotent
Differentiate into cells derived from 3 germ cell layers
Multipotent
Can produce cells of closely related family of cells
Eg HSC cells
Unipotent
Only produce 1 type of cell
but have property of self renewal wich distinguishes them from non stem cells
Transgene
Gene/genetic material transferred from one organism to another
Unconditional KO (knock out)
Gene deleted in all tissues
Targeted KO (knock out)
gene deleted only in specific tissues (eg only in heart, brain ) n at different times ( eg at birth, only after a certain age)
Stem cell plasticity
One type of cell can develop into a cell from a different lineage
Eg bone marrow stem cell and can develop into heart cells
Transdifferentiation
Direct conversion of one differentiated cell type/stem cell to another
Eg haematopoietic stem cell becomes neuronal stem cell
RBC becomes neuron ( though this is less likely)
Induced Pluripotent stem cells ( iPS)
Take ANY adult cell
Put in four genes
And they turn into pluripotent stem cells!!!
Composition of blood
55% plasma
Formed elements:
45% RBC (erythrocytes)
Less than 1% = buffy coat: leucocyte + platelets
Haematocrit
% of volume of RBC in total volume of blood
Should b around 40 something %
Blood cell formation daily
Red cells = 2 x 10^11
White cells = 1 x 10^10
Hemopoietic development dogma
PROLIFERATION & DIFFERENTIATION
The more immature the cell, the more it can proliferate
The more differentiated a cell, the less they can proliferate
So if want to get 10 million WBC a day, must start with a lot of HSCs
Multipotent progenitors (MPP)
‘Committed’ cells
Can form myeloid and lymphoid precursors
Common Myeloid Precursor (CMP)
Megakaryocyte-erythroid progenitor( which gives rise to megakaryocytes n erythrocytes)
Granulocyte-macrophage progenitor
Common lymphoid precursor (CLP)
B T n NK cells
Bipotential progenitors
B-lymphoid/macrophage n
T-lymphoid/myeloid
Long term repopulating cells (LTRC)
Able to produce all blood cell types for the entire life span
Colony forming cells (CFC)
Cells that r alive in culture dish
LTC-IC
Long-term culture initiating cells
ELTC-IC
Extended long-term culture initiating cells
In vitro assays
Done on plate/dish
In vivo assays
Done in whole organism
Eg mice
Short term RC (repopulating cells)
Stem cells that make myeloid n/or lymphoid compartments for a short period of time
CD34+
Surface antigen that stem cells have
Select for cells with these in stem cells assays to find stem cell
Haemopoiesis in embryo
Where
1 mnth: yolk sac then moves to AGM
(Site that will grow Aorta, gonads-testes n ovaries, kidneys)
3 mnths: move to foetal liver n spleen
5 mnths: move to bone marrow cavities
Stoichastic
Concept that stem cell has random commitment to particular lineage
- unlikely
Instructive
Concept that some mechanism in the stem cells tells it which cell it is to become
More likely cos eg get infection, we need more WBC
Done via cell to cell contact wit adjacent cell or signals eg growth factors
Or transcription factors
Colony stimulating factors
‘Growth factors’ to make colonies of n differentiate cells
Bind to receptors on HSC
Can b specific for a particular lineage ir can influence many lineages
120 days
Days RBC lives for
Death of RBC
Lysis in spleen
Separate heme from globin
Get iron from heme - 99% of iron in our bodies get from here!!
Get aa from globin (n we reuse aa)
Erythropoiesis
Makin RBC 2.5 million RBCs/second
5 cells Start wit proerythroblast Erythroblast Normoblast Reticulocyte End wit erythrocyte
Nucleus shrinks, more pink colour as get more haemoglobin
Negative feedbak mechanisms
Driven by erythropoietin ( EPO hormone made from kidneys )
Leukopoiesis
Leucocyte production
B n T progenitors
Granulocyte - macrophage colony forming units
Granulopoiesis
Myeloblast differentiates to
1 basophil
2 neutrophil
3 eosinophil
Thrombopoiesis
Platelet production
Megakaryocyte stays in bone marrow
Stimulated by thrombopoietin to form cytoplasmic extensions
Wich form platelets n r released into blood
Megakaryopoiesis
Making megakaryocytes
Nuclues keeps on multiplying so get like 64n, 128n etc the more N, the more platelets can get
Regulated by thrombopoietin (TPO)
Stem cell factor
Interleukin-6
Monocytopoiesis
Making monocytes
Monocytes can make macrophages n osteoclasts
Regulated by
M-CSF
IL-3
GM-CSF
Thermal dimorphism
Fungi that
At a certain temp, has different morphology eg filamentous
But at another temp, in another form
Antimycotics
Antifungal drug used to treat n prevent mycoses
Targets: Fungal cell membrane Cell wall DNA synthesis Cell division
Protists
Incl protozoa
Algae
Slime moulds
(Apicomplexa)
Can be unicellular or multicellular
