3 research outputs found
Клиничка примена на транскранијалната колор дуплекс
Современите апарати за транскранијалната колор дуплекс сонографија го поврзуваат спектралниот и цликовниот колор приказ во B-mode во реално време
THE HEMOGLOBINS OF THE “FOSSIL FISH” ACIPENSER NACCARII: FUNCTIONAL PROPERTIES AND THEIR STRUCTURAL BASIS
Fish hemoglobins
Vertebrate hemoglobin, contained in erythrocytes, is a globular protein with a quaternary structure composed of 4 globin chains (2 alpha and 2 beta) and a prosthetic group named heme bound to each one. Having myoglobin as an ancestor, hemoglobin acquired the capacity to respond to chemical stimuli that modulate its function according to tissue requirements for oxygen. Fish are generally submitted to spatial and temporal O2 variations and have developed anatomical, physiological and biochemical strategies to adapt to the changing environmental gas availability. Structurally, most fish hemoglobins are tetrameric; however, those from some species such as lamprey and hagfish dissociate, being monomeric when oxygenated and oligomeric when deoxygenated. Fish blood frequently possesses several hemoglobins; the primary origin of this finding lies in the polymorphism that occurs in the globin loci, an aspect that may occasionally confer advantages to its carriers or even be a harmless evolutionary remnant. On the other hand, the functional properties exhibit different behaviors, ranging from a total absence of responses to allosteric regulation to drastic ones, such as the Root effect