Lecture 2
Laboratory Safety and Preparation
- Dress Code and Equipment: Necessity of lab coats, eye protection, and gloves to handle
microbes and prevent contamination.
- Safety Precautions:
- Avoid wearing open shoes; lab coats should cover legs to minimize exposure.
- Hair and loose fabric must be secured to prevent accidents.
- Prohibited Items: Use of mobile phones is strictly banned in the lab to prevent
contamination.
Laboratory Procedures
- Initial Setup:
- Importance of disinfecting bench space with hygiene detergent (e.g., Trigene) to create a
sterile environment.
- Use of Bunsen burners to sterilize the air around the workspace.
- Microbial Work:
- Techniques to maintain a sterile workspace, including minimizing open containers near the
Bunsen burner.
- Procedures for transferring and spreading bacterial cultures while maintaining sterility.
Handling and Disposal of Materials
- Proper disposal methods for microbes, gloves, and other materials using designated
containers (e.g., autoclave buckets, sharps containers).
Laboratory Skills
- Pipetting: Instruction on the correct use of pipettes, emphasizing the importance of
accuracy in measuring liquid volumes.
- Microbial Dispersal and Control: Discussion on controlling microbial growth and
,maintaining a sterile environment in the lab.
Microbial Control Methods
- Definitions: Explanation of terms like antisepsis, sanitisation, disinfection, and sterilisation,
highlighting their differences.
- Mechanical Methods:
- Filtration techniques, including the use of depth filters (e.g., HEPA filters) for air and
membrane filters for liquids.
- Challenges with ultra micro bacteria that can bypass filtration.
Physical Control Methods
- Application of Moist Heat: Using autoclaves to apply moist heat (120°C under pressure)
effectively kills microbes, including Clostridium botulinum. Moist heat penetrates bacterial
membranes better than dry heat.
- Dry Heat: Requires higher temperatures (up to 160°C) and longer exposure times compared
to moist heat. Used for sterilizing items that cannot be moistened.
- UV Radiation: Effective for surface sterilization as it damages microbial DNA but has limited
penetration ability. Suitable for surface cleaning only.
- Ionizing Radiation: Uses electromagnetic radiation to produce reactive molecules that
damage microbial DNA, lipids, and proteins. It penetrates well and is used for sterilizing
packaged food and medical supplies.
Chemical Control Methods
- Phenols: Disrupt proteins and lipids, used historically for medical sterilization.
- Alcohols: Damage microbial cell membranes, used for bench cleaning and hand sanitizing.
- Halogenated Compounds: Release chlorine to sterilize environments, effective in water
treatment.
- Aldehydes: Such as formaldehyde, used in clinical settings for disinfection.
- Quaternary Ammonium Compounds: Detergent-like substances used for surface cleaning.
,- Gases (Ethylene Oxide): Sterilizes medical equipment and packaging materials, highly
effective but hazardous to humans and explosive.
Biological Control Methods
- Bacteriophages (Phage Therapy): Viruses that specifically target and kill bacteria, offering an
alternative to antibiotics, especially as antibiotic resistance increases. Phages adapt to
bacteria, potentially providing a more targeted and less disruptive treatment compared to
broad-spectrum antibiotics.
Practical Applications in Lab
- Sterilization Techniques: Autoclaving for moist heat sterilization, UV light for surface
sterilization, and ethylene oxide gas for sterilizing packaged items.
- Use of Antibiotics in Agar: To selectively grow bacteria or fungi, antibiotics are added to
agar after cooling to avoid heat destruction. Membrane filtration can introduce heat-
sensitive substances into sterile media.
Considerations and Impact
- Environmental Impact of Antimicrobials: Overuse of antimicrobials like triclosan can affect
microbial life in water treatment processes and natural environments, impacting ecosystems.
- Antibiotic Specificity: Different antibiotics target specific bacterial structures, like penicillin
affecting peptidoglycan in gram-positive bacteria, making them effective against certain
types of bacteria but not others.
- Challenges with Fungi: Fungal infections are harder to treat than bacterial infections due to
closer biological similarity to humans, making it difficult to find treatments that do not also
harm human cells.
Lecture 3
Essay Writing Preparation
- Overview of essay component worth 20% of the course mark.
, - Emphasis on choosing a topic, conducting peer-reviewed research, and incorporating
personal interpretation along with factual information.
Essay Submission Guidelines
- Final essay due on April 17th, with a word count of 1000 words.
- Requirement for citing scientific journals and providing personal opinions backed by
references.
- Importance of proper referencing to avoid losing marks.
Peer Review Process
- Introduction to peer review component involving draft submission and feedback exchange
among peers.
- Importance of constructive feedback and learning from others' essays.
- Reflection on the peer review process to improve final essay submission.
- Students are required to submit a draft version of their research essay by a specified
deadline. This draft is part of the assessment and contributes to the course grade.
2. Automatic Allocation for Review:
- Upon submission, each student's draft is automatically allocated to one of their peers for
review. This allocation is facilitated by a tool embedded in the course's learning management
system (LMS), ensuring anonymity and fairness in the assignment of essays for review.
3. Peer Review Training:
- Before beginning the peer review, students must complete a training session. This
training, delivered through an additional assignment on the LMS, aims to equip students
with the skills and knowledge needed to provide constructive and effective feedback.
- The training includes reviewing example essays and marking them according to a rubric,
helping students understand the expectations and criteria for the assessment.
Laboratory Safety and Preparation
- Dress Code and Equipment: Necessity of lab coats, eye protection, and gloves to handle
microbes and prevent contamination.
- Safety Precautions:
- Avoid wearing open shoes; lab coats should cover legs to minimize exposure.
- Hair and loose fabric must be secured to prevent accidents.
- Prohibited Items: Use of mobile phones is strictly banned in the lab to prevent
contamination.
Laboratory Procedures
- Initial Setup:
- Importance of disinfecting bench space with hygiene detergent (e.g., Trigene) to create a
sterile environment.
- Use of Bunsen burners to sterilize the air around the workspace.
- Microbial Work:
- Techniques to maintain a sterile workspace, including minimizing open containers near the
Bunsen burner.
- Procedures for transferring and spreading bacterial cultures while maintaining sterility.
Handling and Disposal of Materials
- Proper disposal methods for microbes, gloves, and other materials using designated
containers (e.g., autoclave buckets, sharps containers).
Laboratory Skills
- Pipetting: Instruction on the correct use of pipettes, emphasizing the importance of
accuracy in measuring liquid volumes.
- Microbial Dispersal and Control: Discussion on controlling microbial growth and
,maintaining a sterile environment in the lab.
Microbial Control Methods
- Definitions: Explanation of terms like antisepsis, sanitisation, disinfection, and sterilisation,
highlighting their differences.
- Mechanical Methods:
- Filtration techniques, including the use of depth filters (e.g., HEPA filters) for air and
membrane filters for liquids.
- Challenges with ultra micro bacteria that can bypass filtration.
Physical Control Methods
- Application of Moist Heat: Using autoclaves to apply moist heat (120°C under pressure)
effectively kills microbes, including Clostridium botulinum. Moist heat penetrates bacterial
membranes better than dry heat.
- Dry Heat: Requires higher temperatures (up to 160°C) and longer exposure times compared
to moist heat. Used for sterilizing items that cannot be moistened.
- UV Radiation: Effective for surface sterilization as it damages microbial DNA but has limited
penetration ability. Suitable for surface cleaning only.
- Ionizing Radiation: Uses electromagnetic radiation to produce reactive molecules that
damage microbial DNA, lipids, and proteins. It penetrates well and is used for sterilizing
packaged food and medical supplies.
Chemical Control Methods
- Phenols: Disrupt proteins and lipids, used historically for medical sterilization.
- Alcohols: Damage microbial cell membranes, used for bench cleaning and hand sanitizing.
- Halogenated Compounds: Release chlorine to sterilize environments, effective in water
treatment.
- Aldehydes: Such as formaldehyde, used in clinical settings for disinfection.
- Quaternary Ammonium Compounds: Detergent-like substances used for surface cleaning.
,- Gases (Ethylene Oxide): Sterilizes medical equipment and packaging materials, highly
effective but hazardous to humans and explosive.
Biological Control Methods
- Bacteriophages (Phage Therapy): Viruses that specifically target and kill bacteria, offering an
alternative to antibiotics, especially as antibiotic resistance increases. Phages adapt to
bacteria, potentially providing a more targeted and less disruptive treatment compared to
broad-spectrum antibiotics.
Practical Applications in Lab
- Sterilization Techniques: Autoclaving for moist heat sterilization, UV light for surface
sterilization, and ethylene oxide gas for sterilizing packaged items.
- Use of Antibiotics in Agar: To selectively grow bacteria or fungi, antibiotics are added to
agar after cooling to avoid heat destruction. Membrane filtration can introduce heat-
sensitive substances into sterile media.
Considerations and Impact
- Environmental Impact of Antimicrobials: Overuse of antimicrobials like triclosan can affect
microbial life in water treatment processes and natural environments, impacting ecosystems.
- Antibiotic Specificity: Different antibiotics target specific bacterial structures, like penicillin
affecting peptidoglycan in gram-positive bacteria, making them effective against certain
types of bacteria but not others.
- Challenges with Fungi: Fungal infections are harder to treat than bacterial infections due to
closer biological similarity to humans, making it difficult to find treatments that do not also
harm human cells.
Lecture 3
Essay Writing Preparation
- Overview of essay component worth 20% of the course mark.
, - Emphasis on choosing a topic, conducting peer-reviewed research, and incorporating
personal interpretation along with factual information.
Essay Submission Guidelines
- Final essay due on April 17th, with a word count of 1000 words.
- Requirement for citing scientific journals and providing personal opinions backed by
references.
- Importance of proper referencing to avoid losing marks.
Peer Review Process
- Introduction to peer review component involving draft submission and feedback exchange
among peers.
- Importance of constructive feedback and learning from others' essays.
- Reflection on the peer review process to improve final essay submission.
- Students are required to submit a draft version of their research essay by a specified
deadline. This draft is part of the assessment and contributes to the course grade.
2. Automatic Allocation for Review:
- Upon submission, each student's draft is automatically allocated to one of their peers for
review. This allocation is facilitated by a tool embedded in the course's learning management
system (LMS), ensuring anonymity and fairness in the assignment of essays for review.
3. Peer Review Training:
- Before beginning the peer review, students must complete a training session. This
training, delivered through an additional assignment on the LMS, aims to equip students
with the skills and knowledge needed to provide constructive and effective feedback.
- The training includes reviewing example essays and marking them according to a rubric,
helping students understand the expectations and criteria for the assessment.
