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Got Iron?
The Silent Battle
What about iron?
O2
O2O2
O2
Too little and too much!
• Deficiency– cellular = cell death– systemic = anemia
• Excess– generation of free
radicals (damage to nucleic acids, proteins, lipid membranes)
Hemochromatosis
Acute Iron Poisoning
• Iron overdose is one of the leading causes of fatality from toxicological agents in children less than 6 years of age.
• Clinical manifestations:– Local toxicity= abdominal pain,
vomiting, diarrhea, GI bleeding
– Systemic toxicity= injury to the cardiovascular system and liver
• Metabolic acidosis
Looks like candy, but can be harmful
Death results usually from shock or liver failure
Are we the only ones that need iron?
Why do microorganisms need iron?
• Cellular Respiration• Electron transport
– These processes result in the formation of ATP for energy
Friends or Foes?
• 99.9% of all bacteria do not cause disease
• Less than 1% are pathogenic and have mechanisms to overcome the host
• Most of these systems involve iron acquisition
Pathogens that readily acquire iron multiply rapidly
• Pathogen = a microorganism that causes disease
– Bacteria – Parasite– Viruses (hijack cell
machinery)
• Mycobacteria
• Salmonella
• Neisseria – (gonorrheoa)– (meningitidis)
• Staphylococcus
• E. coli
• Yersinia
Our innate immune system response to pathogens
Skin and mucosa
• 1st line of defense:– Protective barrier
• Mucous membrane produces substances that fight microbes
Immune cells
• Eat up the invader– Macrophages– Neutrophils – Dendritic cells
• Produce proteins for defense
“The Iron Tug of War”
Fe
Host vs. Invader(additional strategies )
YOU: made by your liver
• Transferrin
• Ferritin
• Lipocalin– siderocalin
Bacteria and parasites
• Siderophores:• Proteins that
bind iron very tightly
– Enterobactin– Salmochelin– Mycobactin– yersinabactin
The fight goes on!The host steals iron back from the invader
Host
Invader
ChelatorGreek word = “claw”
•Biochemical engineers have used bacterial siderophores to help design treatments for patients with iron loading.
What about other metals?
copper role in making neurotransmitters, elasticityof blood vessels, important role in collagen formation, healthy immune system
chromium Involved in the functioning of skeletal muscle.
manganese Antioxidant properties; Fertility; Formation of strong healthy bones, nerves, and muscles;
zinc Needed for:Functioning of many (over 200) enzymes;Strong immune system
Name Function
Nutritional Recommendations
AgeMales(mg/day)
Females(mg/day)
Pregnancy(mg/day)
7 to 12 months
11 11 N/A
1 to 3 years
7 7 N/A
4 to 8 years
10 10 N/A
9 to 13 years
8 8 N/A
14 to 18 years
11 15 27
19 to 50 years
8 18 27
51+ years 8 8 N/A
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