Samantha M. Hurndon Week 11: Week 11: DNA Microarray Journal Club

Definitions

1. Adenocarcinoma is a cancer of an epithelium that originates in the glandular tissue.
2. MALT lymphoma: development of cancer in the B Cells. Rare amoung people under the age of 50 and affects men much more than women. Signs and symptoms: Swelling in the neck , groin and armpit due to enlargement of lymph nodes. Loss of unger and body fatigue, high fever and weight loss. http://maltlymphoma.net/
3. B cells: Help the immune system fight against the invasion of harmful microorganisms into the body. http://maltlymphoma.net/
4. Ablation: Removal or excision. Ablation is usually carried out surgically. For example, surgical removal of the thyroid gland (a total thyroidectomy) is ablation of the thyroid. http://www.medterms.com/script/main/art.asp?articlekey=2089

Outline

1. Abstract
   • Helicobacter pylori is a motile Gram-negative bacterium. This bacterium persists in the human gastric mucosa
   • FliK is the gene that controls hook length during flagellar assembly.
   • Microarry analysis was done on fliK-null mutant, this revealed that under the control of the sigma 54 factor RpoN there is an incase in transcription of genes.
   • Sigma 45 fact is responsible for transcription on the class II flagellar genes (flgE and flgB).
   • Flik is involved in three processes:
     • hook-length control
     • export substrate specificity
     • control of RpoN transcriptional activity
2. Introduction
   • Helicobacter pylori is an infection that causes gastrointestinal disorders (peptic and duodenal ulcers). It is also a predisposing factor of gastric adenocarcinoma and B-cell MALT lymphoma.
   • This is seen often in developing countries due to their living conditions and lack of health care.
   • A key feature of H. pylori is motility, which is required for colonization and persistence. The motility in this bacteria is due to flagella.
   • three RNA polymerase sigma factors (80, 54, 28) control the transcription of H. pulori flagellar genes.
   • There are three classes of regulation
     • Class one: Sigma 80 modulates the transcription of the early flagullar genes.
     • Class two: RpoN deals with the regulation of the middle flagellar structural genes. RpoN is regulated FlgR/FlgS activation system and HP0958
       • Class two regulation encodes hook-length-control proteins.
     • Class three: Transcription of these genes is controlled by FliA (sigma 28) and an anti sigma factor (FlgM).
   • It was observed that the initial annotation of H.pylori genome sequences did not identify all flagellar genes expected by comparison with the Salmonella/Escherichia coli paradigm.
   • Flik in Salmonella controls hook length. In h pylori fliK gene impairs motility. The cells, in both H. pylori and Salmonella, harbor polyhook structures
   • it is suggested that the FliK protein is required to turn off the RpoN regulation during flagullar assembly.
   • In their study they used pan-H.pylori array. The array was based on the genomes of strains NCTC26695 and J99.