Question

Introduction

1. What do these terms mean?

a. Catalase

b. Oxidative stress

c. Pathogen

d. Surfactant

e. Sigma S (RpoS, product of the rpoS gene)

f. Azide

2. What research question are the authors trying to answer?

3. What is the authors’ hypothesis?

4. Why do they want to test activity for HPII on clinical isolates of pathogenic E. coli?

5. What is their rationale for conducting the present study?

Article Link: https://documentcloud.adobe.com/link/review?uri=urn:aaid:scds:US:814b91f5-128c-44b5-806e-faba7dd5ce06#pageNum=1

Answer 1

Ans1: a. Catalase is an enzyme that is found in the peroxisomes and it helps in eliminating oxidative stress by converting hydrogen peroxide to water and oxygen as hydrogen peroxide is harmful for the cell. Lipid metabolism reaction sometimes produces molecules like hydrogen peroxide which needs to be converted to the harmless product as soon as they are synthesized which is carried out by the catalase.

Ans 1 b. Oxidative stress: Presence of highly reactive oxygen radicals like superoxide radicals within the cell are sometimes not get eliminated by the cell antioxidant machinery and cell has to face some harmful effects of these reactive free radicals which are called as oxidative stress. When a cell experiences oxidative stress, it tries to undergo apoptosis.

Ans 1c. Pathogen: Microorganisms that can affect the normal functioning of the cell or human body parts by secreting a toxin or a harmful substance is called pathogen.

Ans 1d. Surfactants are the compounds that can lower the surface tension of the mixture of liquid and gas or a mixture of liquid and solid or between two liquids. Naturally, our lungs tissue secrete surfactant that provides elastic properties to the lung surface and keep the surface tension of the pulmonary fluids low. One example of surfactant is: Dipalmitoylphosphatidylcholine.

Ans 1e: Sigma S or the rpoS, encoded by the gene rpoS, is a 38 kDa protein. In bacterial transcription, the sigma factor is responsible for the initiation of the transcription. rpoS also plays an important regulatory function in transcription and is known to regulate stationary phase of the bacterial growth and transcribed in the late exponential phase of bacterial growth. Many bacterial species use sigma factor switching during sporulation or stress conditions.

Ans 1f: Azide: It is an N₃ anion. It also acts as the inhibitor of the oxidative phosphorylation by binding to the trivalent iron of cytochrome c oxidase of the electron transport chain. It is a poisonous molecule.

Hope this will help you.