2018/2019- Essay 1

Question 1

Title

Describe how deletion mutants of Helicobacter pylori have shown how it clonises the stomach and cause gastric ulcers

Answer 1

Deletion Mutants of Helicobacter pylori: Insights into Stomach Colonization and Gastric Ulcer Formation

Question 2

Introduction- Paragraph 1

Describe how deletion mutants of Helicobacter pylori have shown how it clonises the stomach and cause gastric ulcers

Answer 2

Helicobacter pylori
- Gram-negative ,spiral shaped
- colonises human stomach
- disease: gastrtis, peptic ulcer disease,stomach cancer
- Study of deletion mutants (H.pylori)
- >insights into mechanism by which colonise human stomach
- produces virulence factors
- >pathogenesis
- > persist within hostile stomach environment
- Esaay explores significance of deletion mutants in the pathogenecity og H.pylori.

Question 3

Paragraph 1-Role of deletion mutants in understanding bacterial pathogenesis

Describe how deletion mutants of Helicobacter pylori have shown how it clonises the stomach and cause gastric ulcers

Answer 3

Deletion mutants
* Strains of bacterium in which specific genes/gene segments have been removed/inactivated
* Studying this:
* >scientist determine function of specific genes
* >role in bacterial pathogenesis
* >mechanisms involved in its colonisation of the stomach and development of gastric ulcers

Question 4

Paragraph 2-Essential genes for stomach colonisation

Describe how deletion mutants of Helicobacter pylori have shown how it clonises the stomach and cause gastric ulcers

Answer 4

• H.pylori
• > colonise harsh environment of the stomach lining

Essential genes
* production of urease
* motility

Urease
* Neutralise acidic pH of the stomach
* >creating more favorable environment for survival

Motility
* Helps H.pylori to navigate through the stomach mucus
* Establish persistent infection

Question 5

Paragraph 3-Adhesion factors

Describe how deletion mutants of Helicobacter pylori have shown how it clonises the stomach and cause gastric ulcers

Answer 5

• Attachment to gastric epithelial cells
• > key in H.pylori colonisation
• Deletion mutant helped identify adhesion factors
• > Adhesins
• > > BabA
• > > Sab A
• Bind to specific receptors on stomach lining
• > bacterium adherence and persistence in gastric mucosa

Question 6

Paragraph 4 -Virulence factor and Gastric Ulcer formation

Describe how deletion mutants of Helicobacter pylori have shown how it clonises the stomach and cause gastric ulcers

Answer 6

Virulence factor
* Cytotoxin-associated gene A

CagA deletion mutants
* Studies: involved in disrupting host cell signalling pathway
* >promote inflammation-> ulcer formation

Vac A toxin deletion mutants
* cause damage to gastric epithelium
* contributing ulceration

Virulence factor: Type IV secretion system (T4SS)
Function: allows bacterium to inject proteins:** CagA and VacA ** -> host cells

Deletion mutants
- reduced colonisation ability
- less able to cause gastric ulcers

Suggest:
T4SS- essential to cause stomach infection

• **insights on H.pylori virulence factors **

Question 7

Paragraph 5- Host-Pathogen Interactions

Describe how deletion mutants of Helicobacter pylori have shown how it clonises the stomach and cause gastric ulcers

Answer 7

• Understand host response to infection
• How?
• examine mutants lacking specific genes involved in modulation of the host immune response
• Insights on how H.pylori evades host immune system defenses
• To exbalshic chronic infection

Question 8

Paragraph 6- Conclusion

Describe how deletion mutants of Helicobacter pylori have shown how it clonises the stomach and cause gastric ulcers

Answer 8

• Study of deletion mutants
• Deepened understanding
• > Adhesion factors
• Virulence factors
• Interplay with host immune response

Significance
* development of targeted therepeutic strategies ->infection and gastric disorder
* Molecular tool isights to H.pylori