Microbiology, Complete Module Notes

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2021 – UNIVERSITY - SECOND YEAR MICROBIOLOGY (BIOMEDICINE)


CONTENTS

LECTURE 1: Bacterial Genetics

o Briefly compare the difference between bacterial genetic material and that of a eukaryote
o How is bacterial genetic material replicated?
o Explain how bacteria divides by Binary Fission
o Explain how genetic material can be transferred horizontally between bacteria
o Discuss some of the laboratory techniques that exploit bacterial genetics
o Discuss how knowledge of bacterial genetics has uses in different applications


LECTURE 2: Viral Cultivation

o By the end of this session you should be able to:
o Describe the structure of viruses
o Explain agglutination with specific reference to hemagglutination
o Describe transduction
o Describe phage replication
o Describe replication of animal viruses
o Explain the different methods for growing bacteriophage
o Describe the different methods by which animal viruses can be cultured
o Discuss the pros and cons of each of these methods



LECTURE 3: Yeast, fermentation and food

o Describe the different methods of yeast replication
o Define fermentation
o Discuss a range of uses of microorganisms in the food industry
o Explain how microorganisms provide nitrogen to plants
o Understand the importance of yeast and bacteria in the fermentation processes of a
variety of foods
o Discuss the importance of microorganisms in food spoilage
o Define probiotics
o Describe the importance of bacteria in agriculture explaining the nitrogen cycle and
fixation


LECTURE 4: Biofuels

o List why we need renewable energy sources
o Discuss the role of microorganisms in the production of biogas and bioethanol
o Discuss the ethical issues for and against renewable energy sources
o Discuss the use of algae as a renewable energy source



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LECTURE 5: Waterborne Diseases and Rotavirus

o Explain the use of indicator organisms when testing water quality
o Discuss the importance of water and sanitation and hygiene in preventing water borne
infections
o Understand the significance of rotavirus to global disease burden and discuss prevention
strategies
o Explain how the rotavirus vaccines were developed


LECTURE 6: MICROORGANISMS THAT CAUSE CANCER

o Define cancer
o Provide an example of a bacterial and viral causes of cancer
o Describe HPV infection
o Discuss the development and use of the HPV vaccine
o Distinguish between the cardia and non cardia sections of the stomach
o Discuss how H. plylori causes cardia cancers


LECTURE 7: Skin microflora and staphylococci

o Define the different forms of symbiosis
o Explain what the human microbiome is
o Describe some beneficial effects of the skin microflora
o Describe biofilms
o Discuss the differences between S. epidermidis and S. aureus




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WRITE UP

LECTURE 1: Bacterial Genetics

o Briefly compare the difference between bacterial genetic material and that of a eukaryote

Eukaryote Bacteria
- Linear Double stranded Helix DNA coiled up - Double-stranded
- DNA found in a nucleus, (nucleolus) - Super coiled
- 23 pairs of chromosomes - Single Circular Chromosome
- DNA coiled around histone proteins - Haploid
- All DNA replicates in one go during Mitosis - DNA found in the cytoplasm nucleoid
- Most are Diploid (apart from gametes) - Circular DNA replicates during binary fission
- Lots of non-coding regions in between genes - limited amount of non-coding genes, the
- genetic material cannot be transferred longer a bacteria genome the more genes it has
between cells (at least not naturally) incorporated
- Each gene has its own operon - All adjacent genes have a single operon
- Contains smaller circular, double stranded
DNA strands: Plasmids
- Plasmids replicate independently from
Chromosomal DNA
- Plasmids often contain and express beneficial
genes for the organism (such as antibiotic
resistance
- Plasmids may be transferred between bacteria


o How is bacterial genetic material replicated?
1) During cell division (binary fission), cells begin to elongate
2) DNA replicates before the cell divides:
 Supercoiling is relaxed by topoisomerase or gyrase
 Two strands are unwound by Helicase
 New DNA is synthesised by DNA polymerase
 Point at which replication occurs is called the replication fork
 Once the DNA has replicated the two loops are separated by the enzyme
topoisomerase
3) Cell divides




Topoisomerase




Helicase




Polymerase




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o Explain how bacteria divides by Binary Fission
 A series of proteins called Fts proteins are involved with bacterial division
 After the DNA replicates a ring of FtsZ forms precisely in the middle of the cell
 This ring recruits other Fts proteins to form the divisome complex
 The proteins in the divisome are involved with the synthesis of peptidoglycan and a new
cell membrane called the division septum in the centre of the cell
 When there is twice as much new material the cells divide
 The time it takes for bacteria to divide (or double) is called the generation time
 The inheritance of genetic material from one generation to another is known as vertical




gene transfer

o Explain how genetic material can be transferred horizontally between bacteria
 Bacteria can exchange genetic material with bacteria in the same generation. This is
known as horizontal gene transfer
 This can occur through 3 different mechanisms:
 Transformation
 Conjugation
 Transduction

Transformation:
 A process by which a bacterial cell can take up bacteria from the environment.
 In nature bacteria release DNA into environment (probably after death and cell
lysis). Competent bacteria then encounter the naked DNA and take it up
Conjugation:
 Requires a plasmid
 There must be cell to cell contact
 Only one cell can contain the plasmid
 Conjugation occurs via pilli (Gram –ve bacteria)
 Conjugation occurs via sticky surface molecules (Gram +ve bacteria)




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