BL

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