5.1. Notes_ Damage to Host Cells [ ± 60 min ] _ Eduvos

What do most parasites aim to do with their hosts?

They usually aim to keep their hosts alive long enough to obtain nutrients or reproduce.

What happens when a microbe overpowers the host's defenses?

Disease results.

What are siderophores?

Clever proteins used by some pathogens to scavenge iron from the host.

How do siderophores assist bacteria in survival?

They bind to iron more tightly than the host's own proteins, allowing bacteria to absorb iron.

What are the three ways pathogens damage host cells?

Using nutrients, causing direct damage, and producing toxins.

What does direct damage from pathogens entail?

Disrupting host cell function, producing waste products, and metabolizing and multiplying inside host cells.

What is one way bacteria can trick host cells for their advantage?

By inducing host cells to engulf them, allowing bacteria to multiply inside.

What are toxins?

Poisonous substances produced by bacteria that can cause serious damage to host cells.

What does toxigenicity refer to?

The ability of a bacterium to produce toxins.

What is toxemia?

When toxins enter the host's bloodstream, causing widespread damage.

What is a toxoid?

An inactivated form of a toxin used in vaccines.

What are antitoxins?

Antibodies specifically created to neutralize toxins.

What are exotoxins?

A type of toxin produced and released by bacteria that can cause disease.

What makes exotoxins particularly dangerous?

They spread easily, are made of proteins, and are effective at causing damage.

What is the significance of the LD50 measurement?

It indicates the amount of toxin required to kill 50% of a test population; lower LD50 means higher potency.

Which bacteria produce leukocidins?

S. aureus, which kills white blood cells and weakens the immune response.

What are superantigens?

Toxins that overwhelm the immune system by overstimulating T-cells.

What causes cytokine storms?

Overproduction of cytokines due to stimulation by superantigens.

Where do endotoxins come from?

They are part of the cell wall of Gram-negative bacteria and are released when the bacteria die.

What is a notable effect of endotoxins?

They can trigger severe immune responses, including fever and shock.

How do antibodies relate to endotoxins?

The body uses antibodies to fight the bacteria producing endotoxins, but they cannot neutralize the endotoxins themselves.

What are mycotoxins?

Toxins produced by fungi that can cause a range of health issues.

How can fungi cause chronic infections?

By provoking allergic responses or producing irritating waste products.

What is one effect of the fungus Fusarium?

It produces trichothecene toxins that inhibit protein synthesis in host cells.

What type of toxin is produced by Claviceps?

Ergot toxin, which can cause hallucinations and gangrene.

What strategy do protozoa use to avoid host defenses?

They can grow in phagocytes and change their surface proteins to evade detection.

What harm can helminths cause in a host?

They can latch onto tissues, disrupt functions, and steal nutrients.