Microbiology

The spike protein mediates receptor binding and membrane fusion. It's the most exposed surface protein and elicits the strongest neutralizing antibody response, making it the vaccine target.

Pseudomonas aeruginosa produces alginate, a viscous polysaccharide exopolymer that forms the biofilm matrix, protecting bacteria from antibiotics and immune responses. This is characteristic of chronic respiratory infections.

Integration is the process by which retroviral DNA (synthesized via reverse transcriptase) becomes incorporated into host genomic DNA. This establishes persistent infection and can cause insertional mutagenesis.

Flagellin comprises the helical filament and constitutes the H (Hauch) antigen, used for serotyping bacteria like Salmonella. Other flagellar components are internal and less immunogenic.

Mycolic acids in the mycobacterial cell wall resist acid-alcohol decolorization, causing the characteristic acid-fast staining. These long-chain fatty acids are unique to mycobacteria.

Beta-lactamase enzymatically cleaves the beta-lactam ring of penicillin, inactivating the antibiotic. This is enzymatic degradation, not target modification or pump-mediated resistance.

Positive-sense RNA can directly serve as mRNA for ribosomal translation. Replication requires RNA-dependent RNA polymerase. This genome type doesn't undergo reverse transcription or DNA synthesis.

Pseudomonas aeruginosa is a gram-negative, oxidase-positive rod commonly causing respiratory infections in hospitalized patients. E. coli and Klebsiella are oxidase-negative, while Proteus is also oxidase-negative.

RFLP uses restriction endonucleases to cut DNA at specific recognition sequences, creating fragments of variable lengths used for genetic analysis and bacterial strain identification.

Streptococcus mutans is the primary causative agent of dental caries (cavities). It produces lactic acid from carbohydrate fermentation, demineralizing tooth enamel. Other listed bacteria cause different infections.