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Ch. 15 - Microbial Mechanisms of Pathogenicity
Tortora - Microbiology: An Introduction 14th Edition
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398Not the one you use?Change textbook
Chapter 15, Problem 10

The Opa gene is used to identify this endotoxin-producing bacterium that grows well in the high- CO₂ conditions inside phagocytes.

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Identify the bacterium described by the problem: it produces endotoxin, grows well in high-CO₂ conditions inside phagocytes, and is associated with the Opa gene.
Recall that the Opa gene encodes opacity-associated proteins involved in bacterial adherence and invasion, which is characteristic of Neisseria species.
Understand that endotoxins are lipopolysaccharides (LPS) found in the outer membrane of Gram-negative bacteria, such as Neisseria gonorrhoeae and Neisseria meningitidis.
Recognize that Neisseria gonorrhoeae is known for expressing Opa proteins and thriving in high-CO₂ environments, especially inside phagocytic cells.
Conclude that the bacterium identified by the Opa gene and described conditions is Neisseria gonorrhoeae.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Opa Gene and Its Role in Bacterial Identification

The Opa gene encodes opacity-associated proteins found in certain bacteria, notably Neisseria species. These proteins facilitate bacterial adhesion and invasion of host cells, making the Opa gene a useful molecular marker for identifying these pathogens.
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Endotoxins in Gram-negative Bacteria

Endotoxins are lipopolysaccharide components of the outer membrane of Gram-negative bacteria. They trigger strong immune responses and are key virulence factors, helping to identify bacteria that produce them, such as Neisseria gonorrhoeae.
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Bacterial Growth in High CO₂ Environments Inside Phagocytes

Some bacteria, like Neisseria species, thrive in high CO₂ conditions found inside phagocytic cells. This adaptation allows them to survive and multiply within host immune cells, contributing to their pathogenicity and aiding in their identification.
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