Given below are two statements Statement (): Human DNase | is... | Agrigyan

• Poliovirus Vaccines:
• Salk Vaccine (IPV): Developed by Jonas Salk in 1953 (licensed in 1955). It is an inactivated (killed) poliovirus vaccine produced by growing poliovirus serotypes 1, 2, and 3 in monkey kidney cell cultures, followed by chemical inactivation with formaldehyde. Administered by intramuscular injection.
• Sabin Vaccine (OPV): Developed by Albert Sabin in 1961. It is a live attenuated oral virus vaccine that replicates in the gut mucosa, stimulating mucosal IgA immunity.
• Conclusion: Salk polio vaccine is a killed virus vaccine (Option 2).

Correct option: (2) Killed virus

• Assertion (A): True. Acidophilic chemolithoautotrophic sulfur-oxidizing bacteria (such as Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans) play an important industrial role in the pre-combustion processing of high-sulfur coal.
• Reason (R): True. These microorganisms carry out biodesulfurization of coal by biologically oxidizing inorganic pyrite ($\text{FeS}_2$) into soluble sulfate and ferric iron according to the reaction:

Removing the pyritic sulfur prior to coal combustion prevents the formation and atmospheric emission of sulfur dioxide ($\text{SO}_2$), which causes acid rain.

• Relationship: Reason (R) provides the direct scientific rationale and mechanism for the industrial application stated in Assertion (A) (Option 1).

Correct option: (1) Both (A) and (R) are true and (R) is the correct explanation of (A)

• Endophytic Diazotrophs in Sugarcane:
• Acetobacter diazotrophicus (now Gluconacetobacter diazotrophicus): An obligate or facultative acidotolerant endophytic diazotroph discovered by Döbereiner and colleagues in Brazil (1988). It colonizes the internal root tissues, stem vascular parenchyma, and intercellular apoplastic fluid of sugarcane (Saccharum officinarum).
• Ecological Characteristics: It thrives in sugar-rich environments (up to $10\%$ sucrose) and low $pH$ ($pH \sim 3-5.5$), fixing significant amounts of atmospheric nitrogen that directly benefit the host crop.
• Other Diazotrophs:
• Azospirillum lipoferum: Associative rhizospheric diazotroph of cereals.
• Azotobacter chroococcum: Free-living aerobic diazotroph in soil.
• Klebsiella oxytoca: Facultative anaerobe.
• Conclusion: Acetobacter diazotrophicus is the endophytic diazotroph of sugarcane (Option 4).

Correct option: (4) Acetobacter diazotrophicus