Adaptations against heme toxicity in blood-feeding arthropods.
A blood-sucking habit appeared independently several times in the course of arthropod evolution. However, from more than a million species of insects and arachnids presently living on earth, only about 14,000 species developed the capacity to feed on vertebrate blood. This figure suggests the existence of severe physiological constraints for the evolution of hematophagy, implying the selective advantage of special adaptations related to the use of blood as a food source. Digestion of vertebrate hemoglobin in the midgut of blood-feeding arthropods results in the production of large amounts of heme, a potentially cytotoxic molecule. Here we will review mechanisms by which heme can exert biological damage, together with a wide spectrum of adaptations developed by blood-feeding insects and ticks to counteract its deleterious effects. In spite of the existence of a great molecular diversity of protective mechanisms, different hematophagous organisms developed convergent solutions that may be physiologically equivalent.
Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude, Av. Brigadeiro Trompowsky, s/n, Cidade Universitária, Ilha do Fundão, 21941-690 Rio de Janeiro, RJ, Brazil.
Aurélio V
AV
Graça-Souza
Clarissa
C
Maya-Monteiro
Gabriela O
GO
Paiva-Silva
Glória R C
GR
Braz
Márcia C
MC
Paes
Marcos H F
MH
Sorgine
Marcus F
MF
Oliveira
Pedro L
PL
Oliveira
D000222:Adaptation, Physiological; D000818:Animals; D000975:Antioxidants / Q000502:physiology; D001181:Arthropods / Q000469:parasitology / Q000502:physiology*; D005247:Feeding Behavior; D006418:Heme / Q000378:metabolism*; D006420:Hemeproteins / Q000502:physiology; D015227:Lipid Peroxidation; D018384:Oxidative Stress
D000975:Antioxidants; D006420:Hemeproteins; D006418:Heme