Clostridium Botulinum

Antibodies (Human)

The ‘foot’ (bottom) of the antibody is known as the Fc fragment - binds to cells, binds to complement = effector function (kills or removes antigen)

The top (antigen binding) is the Fab fragment

Chains are held together with disulphide binds

Associated molecules allow intracellular signalling 

Normally 3X constant heavy chain domains per chain and a hinge region (except μ and ε which have 4 and no hinge region)

Classes of Immunoglobulins

The five primary classes of immunoglobulins are IgG, IgM, IgA, IgD and IgE,  distinguished by the type of heavy chain found in the molecule. 

IgG - gamma-chains

IgMs - mu-chains

IgAs - alpha-chains

IgEs - epsilon-chains

IgDs - delta-chains.

Differences in heavy chain polypeptides allow different types of immune responses. The differences are found primarily in the Fc fragment. There are only two main types of light chains: kappa (κ) and lambda (λ), and any antibody can have any combination of these 2 (variation).

IgG 

monomer

Gamma chains

70-85% of Ig in human serum. 

secondary immune response 

only class that can cross the placenta - protection of the newborn during first 6 months of life

principle antibody used in immunological research and clinical diagnostics

21 day half life

Hinge region (allows it to make Y and T shapes - increasing chance of being able to bind to more than one site)

Fc strongly binds to Fcγ receptor on phagocyte - opsono-phagocytosis

Activates complement pathway

IgM

Serum = pentamer 

Primary immune responses - first Ig to be synthesised

complement fixing 

10% of serum Ig 

also expressed on the plasma membrane of B lymphocytes as a monomer - B cell antigen receptor

H chains each contain an additional hydrophobic domain for anchoring in the membrane

Monomers are bound together by disulfide bonds and a joining (J) chain.

Each of the five monomers = two light chains (either kappa or lambda) and two mu heavy chains.

heavy chain = one variable and four constant regions (no hinge region)

can cause cell agglutination as a result of recognition of epitopes on invading microorganisms. This antibody-antigen immune complex is then destroyed by complement fixation or receptor mediated endocytosis by macrophages.

In humans there are four subclasses of IgG: IgG1, IgG2, IgG3 and IgG4. IgG1 and IgG3 activate complement.

IgD 

B cell receptor

<1% of blood serum Ig

has tail pieces that anchor it across B cell membrane

forms an antigen specific receptor on mature B cells - consequently has no known effector function (don’t kill antigens, purely a receptor) (IgM as a monomer can also do this)

IgE 

Extra rigid central domain

has the most carbohydrates

IgE primarily defends against parasitic invasion and is responsible for allergic reactions.

basophils and tissue mast cells express very high affinity Fc receptors for IgE - mast cells then release histamine

so high that almost all IgE is bound

sensitizes (activates) mucosal cells and tissues 

protects against helminth parasites

IgE’s main purpose is to protect against parasites but due to improved sanitation these are no longer a prevalent issue across most of the world. Consequently it is thought that they become over activated and over sensitive while looking for parasites and start reacting to eg pollen and causing allergies.

IgA

Exists in serum in both monomeric (IgA1) and dimeric (IgA2) forms (dimeric when 2 Fcs bind via secretory complex)

15% of the total serum Ig.

4-7 day half life

Secretory IgA2 (dimer) = primary defense against some local infections

Secreted as a dimer in mucous (e.g., saliva, tears)

prevents passage of foreign substances into the circulatory system

Isotype: class of antibody (IgD, IgM etc)

Allotype: person specific alleles 

Idiotype: (hyper) variable region - antibody specificity 

Schematic of gram positive diplococci (Streptococcus pneumoniae): Note that the diplococci are lancet shaped

Review sheets from my microbiology exam last Monday 🔬

Motivation can be experienced differently for each of us. While some people just get this kind of impulsive motivation, others develop their motivation through actions.

@masterposts @studymasterposts

I would like to show you why it is wrong to wait for your motivation and why you should just do something instead - it doesn’t matter how big your action is.

How to gain motivation

OK, so just like I told you above there exists a concept of just doing some random shit. That means that you start small even though you know that you should do more.

You need to write an essay in two days but you’re spending all the time watching a cat jumping from a window? (if you followed the link - yeah, it’s funny but please continue reading my bullshit lol)

The solution to your stressful task is to start doing something even if it doesn’t seem big or challenging. (In our example with the essay this would mean, starting the writing program/ writing “Outline for my essay” on a paper/ starting a draft as small as possible etc.)

You need to clean your room? Search the smallest task and do this one: put your old pizza that’s laying on the floor in the trash can and your underwear where it belongs - you don’t want your dog to eat it, right?

You want to get fit and start working out? Maybe you had an impulse of motivation one week ago, but now you’re laying on the couch like the cutest panda ever, eating sweets and asking yourself where your motivation went.

You already have an idea what you need to do now, right? Just do one push-up/ lunge/ crunch whatever.

It doesn’t matter how small your action is, but if you experience the feeling of this small success you’ll keep going.

How to stay motivated (Part 1)

Now that you’re finally motivated (doesn’t matter how), you really need to stick on that workflow or whatever you’re trying to achieve. One of the simplest things to maintain your motivation is to think of why you started. Here are some examples:

I know that I’m able to get this shit done.

I want to prove that I can do more than I thought.

I want to show everybody that I’m taking my responsibilities seriously.

I need to pass that exam.

Failing is worse than studying.

etc. (the reason needs to come from your heart - if it isn’t true, it won’t work)

Another way (which is pretty simple and works pretty good for most of the people) is the chain system: 

Draw 31 boxes (for one month) and tick one each day after completing your task. This method is pretty common because it is pretty simple and works for no matter how much time you want to do your habit. (The lovely @emmastudies has created a lot of wonderful printables, maybe you find more details there for study tracking.) After keeping up with the growing chain, you’ll be thinking twice before interrupting the chain and stopping your chain.

Part 2 will be posted on Friday, 06.01.

05-11-18 bio notes! i tried out a new background and i think it looks really pretty!! i hope you guys like it :). i had my first test for my dissection lab and my group ended up getting 100%! the next few tests are harder, but i think we’ll all do gr8. i hope you all had a great week!

Sooo I’m studying microbiology 2:28 am because I’m a desperate bitch Microbiology + immunology = total final grade I got a 10 in my immunology test so I’m PRAYING for a 10 in microbiology so I can get a bIG BeauTiFul 10 on my final

April Background

I created this new background for April! A reminder to all the great girls out there who are awesome human beings!

For a high quality foto, check out the link in my previous post!

Normal Flora

Blood, Spinal Fluid, Urine: sterile

Cutaneous surfaces (urethra, outer ear included): Staph epidermidis, Staph aureus, Corynobacteria (dyphteroids),Streptocci, Candida spp

Nose: Staph aureus, Staph epidermidis, dyphteroids, assorted streptococci

Gingival crevices: anaerobes = Bacterioides/Prevotella, Fusobacterium, Streotococci, Actinomyces

Oropharynx: Viridans group (alpha hemolytic strep), Neisseria (non pathogenic), H. influenzae (non typeable, meaning, w/o capsule), Candida albicans

Stomach: none

Breast-fed babies colon: microaerophilic/anaerobic = Bifidobacterium, Lactobacillus, streptococci.

Adult Colon: microaerophilic/anaerobic = Bacteroides/Prevotella, E.coli, Bifidobacterium, Eubacterium, Fusobacterium, Gram- anaerobic rods, Lactobacillus, E.faecalis, streptococci

Vagina: Lactobacillus, streptococci, diphteroids, yeasts, Veillonella, Gram- rods

desmosome a circular, dense body that forms the site of attachment between certain epithelial cells, especially those of stratified epithelium of the epidermis, which consist of local differentiations of the apposing cell membranes.

-Exfoliatin

A staphylococcus toxin - Cleaves the desmosomes in the stratum granulosum - Separates layers of skin. - Example: Scalded skin syndrome (occurs more often in infants)