Bacteria And Fungi In Petri Dishes

Antimicrobial Agents  - Cell wall inhibitors

Based on mode of action • divided into families based on chemical structure

 Modes of action Interference with: 

cell wall synthesis 

protein synthesis 

nucleic acid synthesis 

plasma membrane integrity 

metabolic pathway 

Inhibitors of Bacterial Cell Wall (peptidoglycan) Synthesis 

The Beta-lactam Family 

The Glycopeptides 

Peptidoglycan is composed of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) repeat units, and amino acids.  Each NAM is linked to peptide chain and the peptide chains are cross-linked.

β-lactams 

Includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems.

class of broad-spectrum antibiotics containing a β-lactam ring

Bacterial transpeptidase enzymes are responsible for catalysing cross-linking of the peptide chains

β-lactam ring bind to these transpeptidases – this inhibits cross-linking between peptide chains and prevents synthesis of stable PG

Cell wall synthesis ceases and the bacterial cells eventually die due to osmotic instability or autolysis. 

Glycopeptides 

Polypeptide agents - basic structural elements amino acids 

Vancomycin: 

complexes with peptide portion of peptidoglycan’s precursor units 

vancomycin is a large hydrophilic molecule able to form hydrogen bonds with the terminal D-alanyl-D-alanine moieties of the NAM/NAG-peptides

preventing PG transglycosylation reaction – PG precursor subunits (NAG-NAM+peptide) cannot be inserted into peptidoglycan matrix;

Vancomycin also alters bacterial-cell-membrane permeability and RNA synthesis

Uses:  serious Gram positive infections e.g. MRSA wound infection

Adverse effects:

damage to auditory nerve 

hearing loss (ototoxicity) 

“Red man/neck” syndrome - rash on face, neck, upper torso 

Haematology

White Blood Cells (Leukocytes)

Neutrophils, eosinophils and basophils = granulocytes (polymorphonuclear leukocytes)

Monocytes & lymphocyes = mononuclear

Neutrophils

Most numerous (~60% of WBC)

Nucleus divided into lobes

Cytoplasm contains small granules

Stains pink with Romanowsky dyes

Lifespan of 6-10hrs

Exit into tissues - non-specific defence against bacteria and fungi

Eosinophils

1% of circulating leukocytes 

Large cytoplasmic granules - stain strongly with acidic dye eosin

Nucleus is bilobed

Circulate for 4-5hrs

Exit to tissues –> 

Defence against parasites 

Dampen allergic response

Tissue eosinophils are also capable of responding to bacterial and fungal infection in a similar way to neutrophils.

Basophils

Least numerous (<1%)

Large granules stain strongly with basic dye methylene blue

Involved in anaphylactic hypersensitivity and inflammatory reactions

Monocytes

5% of circulating leukocytes

Large cell

Kidney/clefted shaped nucleus

Scattering of delicate azurophilic granules

Circulate for 10hrs

Mature into phagocytic tissue macrophages

Responsible for the removal of aged RBCs and other debris

Process and present antigens to T-lymphocytes 

(Macrophages are formed in response to an infection or accumulating damaged or dead cells. Large, specialized cells that recognize, engulf and destroy target cells.)

Lymphocytes

Second most common leukocyte (33%)

Much less cytoplasm - nucleus almost fills cell

Variable lifespan

Receptors on surface recognise foreign substances

Several types of lymphocyte - click here

hey! could you do a study tips post on studying w friends who aren't doing the same subjects? like, how to make good flashcards/questions and answers etc so they can quiz you and give you hints etc even if they don't know the content?

How to Effectively Study with Friends

Using Flash Cards

Oh easy peasy! Simply write examination style questions on your flashcards - that way when your friends read the questions out to you, you’ll be testing yourself in a way that might show up on the easier exam questions. Reason being that in order to cover all the topics, your questions will tend to be somewhat simple e.g. describe the different components of x, explaining how they related to y. Obviously, flash cards aren’t the best way to study more complex interrelationships between ideas/concepts, which should be explored more in a mind map fashion. For tips on mind maps, you can check out my briefing here. 

Using Your Existing Study Notes

Other than flash cards, if you intend to study in groups for most subjects, one of the best ways to do that is to use the Cornell Notetaking System (which you can read about with my personal tips here). Writing the questions out as you study saves you the trouble of writing out questions for your friends to test you on, and as well as that, means you can test yourself almost as well without them for any times when you’re studying solitary. 

Using Essay or Long Response Questions

For long response essays, it’s better to use principles like the rubber duck method, i.e. explaining how concepts relate to each other as if the other person doesn’t know anything about it. So give your friends a list of essay questions and explain part by part in a logical sequential order how you would answer that question e.g. I would talk about the involvement of person A in event B, and explain their impact through examples C, D and E, etc. 

Choosing the Right Study Group 

Most of all, make sure you rally and encourage each other. Work with people who are like-minded, rotate between each other and have someone who will keep the others on task when you start getting too carried away when studying. Having a goal on what you intend to get finished during a group study session will make sure you always get more out of the session than studying alone!

Hope that helps! ^_^

I made a lymph drainage sticker for the immuno section of first aid

You can get the Sticker here: https://www.redbubble.com/people/histrionicole/works/29980305-lymph-node-drainage?asc=u&p=sticker

ETC shortcuts

FADH2 goes to complex II since 2 hydrogens

RotenONE inhibits complex ONE

AntImIcIn A, 3 III’s ==> Antimycin A inhibits complex 3

Cyan COlored Complex IV ==> Cyanide and CO inhibit complex IV

24 brown fatty aspirins break up ==> 2,4 dnp, aspirin and brown fat are etc uncouplers 

Biochem enzymes MNEMONIC

“ABC” enzymes

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“TLC For Nancy” (TLCFN) Coenzymes & Cofactors

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Thiamine PyroPhosphate -TPP- requiring enzymes (B1)

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Pirydoxine (B6) coenzyme

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Cyanocobalamine (B12) coenzyme

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Succynil CoA source: “VOMIT”

Cysteine Growth Requirements

MICROBIOLOGY MNEMONIC

BoyFriend Lost Penis

B rucella

F rancisella

L egionella

P asteurella

or….

The four sisters “Ella” worship in the “cystein” chapel

Brucella

Francisella

Legionella

Pasteurella