Lab exam 205-2

Module 1: Biosafety

Anthrax

• Bacillus anthracis

  • Gram-positive, rod-shaped bacterium

  • Classified as Hazard group 3 pathogen

  • Forms resistant spores

• Transmission & Toxins

  • Spreads via spores (through grazing animals, air)

  • Produces toxins; polyglutamic capsule complicates immune response

Laboratory Biosafety

• Biosafety Levels (1-4)

  • Basic to Maximum containment

  • Different practices and safety equipment for each level

• Biosafety Cabinets

  • Class I, II, III: Protection for operators, work, and both

• Negative Pressure Flow

  • Technique to prevent airborne agents from escaping

Personal Protective Equipment (PPE)

• BSL-3 lab PPE protocols

• Proper donning and doffing procedures

Staff Actions and Responsibilities

• Buddy system, sign-in, training, and security protocols

• Mandatory training requirements for safe lab operation

Setting Up Culture in BSL 3

• Class III mode safety protocols for large cultures

Safe Microbiological Techniques

• General lab safety practices (e.g., decontaminating spills, reducing aerosols)

• Mouth pipetting and biological waste handling

Sample Preparation & Sterility Testing

• Steps for ensuring sterility of samples before removal from the lab

Fumigation and Lab Decontamination

• Methods and guidelines for fumigating the lab

Exiting the Lab

• Disinfection, waste disposal, and staff sign-out procedures

Module 2: Pipetting

Serial Dilution

• Process and techniques for performing serial dilution in microbiology

Sterilization

• Autoclaving procedures for sterilizing medium and containers

Microliter Pipette

• Uses, techniques, and importance in precise measurement

Coomassie Blue Dye

• Uses in protein staining (anionic = blue, cationic = green/red)

Bradford Assay

• Colorimetric method for determining protein content

Module 3: Microscopy & Bacterial Structures

Bacterial Structures

• Motility: Flagella, fimbriae, pili, chemotaxis, biofilm formation

• Morphology: Gram-positive vs. Gram-negative cell walls, capsule formation

Bacterial Intracellular Components

• DNA, ribosomes, and plasmids in bacteria

Microscopy Techniques

• Light Microscopy: Resolution limits, immersion oil

• Staining Methods: H&E, Mallory, and others

• Electron Microscopy: TEM and Fluorescence microscopy

Bacterial Cell Types and Functions

• Prokaryotes vs. Eukaryotes

• Bacterial outer cell structures, adhesion, and movement

Module 4: Gram Stain

• Overview and importance in bacterial identification

Module 5: Pasteurization & Sterilization

Heat Treatment

• Pasteurization vs. Sterilization: Methods and purposes

• LTLT and HTST pasteurization

• Sterilization at temperatures above 100°C

Canning & UHT

• Canning process and sterilization via autoclave

• Ultra-high temperature (UHT) sterilization

Food pH & Spoilage

• pH levels in food and their impact on microbial growth

• Microbial foodborne illnesses: Food intoxication vs. infection

Shelf-life & Spoilage Testing

• Methods of measuring food quality and spoilage

Food Packaging

• Impact on food preservation and microbial contamination

Module 6: Bacterial Isolation

Salmonella

• Characteristics, growth conditions, and BSL-2 containment

• Salmonella Shigella Agar (SSA) for isolation

Microbial Growth

• Factors affecting microbial growth: Temperature, pH, nutrients, etc.

• Methods for isolating and culturing microorganisms (e.g., streaking, nutrient broth)

Sterile Technique & Aseptic Technique

• Best practices for maintaining sterility during lab work

Module 7: Bacterial Growth Curves

Growth Phases

• Lag, Log, Stationary, and Death phases

• Nt = N0 * 2^n growth calculation