Fate of blood meal iron in mosquitoes

Abstract

Iron is an essential element of living cells and organisms as a component of numerous metabolic pathways. Hemoglobin and ferric-transferrin in vertebrate host blood are the two major iron sources for female mosquitoes. We used inductively coupled plasma mass spectrometry (ICP-MS) and radioisotope-labeling to quantify the fate of iron supplied from hemoglobin or as transferrin in Aedes aegypti. At the end of the first gonotrophic cycloe, ~87% of the ingested total meal heme iron was excreted, while 7% was distributed into the eggs and 6% was stored in different tissues. In contrast, 8% of the iron provided as transferrin was excreted and of that absorbed, 77% was allocated to the eggs and 15% distributed in the tissues. Further analyses indicate that of the iron supplied in a blood meal, ~7% appears in the eggs and of this iron 98% is from hemoglobin and 2% from ferrictransferrin. Whereas of iron from a blood meal retained in body of the female, ~97% is from heme and <1 % is from transferrin. Evaluation of iron-binding proteins in hemolymph and egg following intake of 59 Fe-transferrin revealed that ferritin is iron loaded in these animals, and indicate that this protein plays a critical role in meal iron transport and iron storage in eggs in A. aegypti.

Multiple ferritins are vital to successful blood feeding and reproduction of the hard tick Haemaphysalis longicornis

“…Failure of ferritinsilenced ticks to lay eggs may be due to insufficient nutrients, including iron, required for optimum egg production (Zhou et al, 2007). Our results suggest that HlFER2 is important during oviposition and embryonic development.…”

“…The blood meal of female mosquitoes provides iron, which is required for optimal egg development and offspring viability (Zhou et al, 2007). In female ticks, initiation of the reproductive cycle necessitates a blood meal.…”

Antimalarial Iron Chelator FBS0701 Blocks Transmission by Plasmodium falciparum Gametocyte Activation Inhibition

“…However, mosquitoes start the process of blood meal digestion immediately after feeding is completed. During this process, large amounts of hemoglobin from the RBCs are released and degraded, which results in an increase in free heme iron in the midgut (40). It is possible that the large amounts of free iron released during RBC hemoglobin digestion bind to FBS0701 and compromise its inhibitory effect against the mosquito midgut stages of the parasite.…”

Characterization of the Achromobactin Iron Acquisition Operon in Sodalis glossinidius

“…In blood-feeding insects, iron is a component of blood meal hemoglobin and is sequestered within host storage molecules, including heme, transferrin, ferritin, and iron-containing proteins (11)(12)(13). Sodalis has several putative iron acquisition systems, including a siderophore system that synthesizes and transports the siderophore achromobactin (14,15).…”