Oxygen consumption in burrowed and unburrowed ammocoetes of Lampetra planeri (Bloch).
Abstract 1. 1. At 15°C, the attainment of a constant rate of oxygen consumption took up to approximately 3 hr in burrowed and 12 hr in unburrowed ammocoetes. 2. 2. The rate in acclimated ammocoetes (mean wet wt. l·34g) burrowed in the light and dark was 41·7 and 40·1 μl/g per hr respectively and in unburrowed animals under the same regimes was 69·0 and 55·7 μl/g per hr. 3. 3. These results clarify conflicting previous recordings and indicate that ammocoetes have a very low metabolic rate.
Hæmoglobin Pattern of the Cyclostome Pertromyzon planeri during the course of Development
Two hæmoglobin components have been demonstrated by starch gel electrophoresis in both larval and adult forms of Petromyzon planeri1. Although the components are most clearly separated by electrophoresis in starch gel, separation has also been obtained by starch block electrophoresis and on acetate cellulose paper. Furthermore, after elution of the individual bands it was found that each one then runs as a single component in the starch gel system (Fig. 1). It seems therefore quite likely that the separation in the different hæmoglobin bands is due to differences in molecular size. Concerning the electrophoretic mobility of these hæmoglobins as compared to human ones it must be noted that their isoelectric point, unlike that of other species of lampreys2, seems to be in the region of neutrality.
ON THE EVOLUTION OF HEMOGLOBIN. RESPIRATORY PROPERTIES OF THE HEMOGLOBIN OF THE CALIFORNIA HAGFISH, POLISTOTREMA STOUTI
1. Oxygen equilibria of hagfish hemoglobin inside and outside the red blood cell have been obtained under a variety of conditions. The oxygen affinity of the hemoglobin in the erythrocyte suspensions is high (p50 = 3-4 mm. Hg at 18°), although it is even higher in hemoglobin solutions (p50 = 1.8 mm. Hg at 18° C.). There is no interaction between hemes (n = 1.00) and virtually no Bohr effect. The effect of temperature on the oxygen equilibrium of hagfish hemoglobin is similar to that observed in recent experiments on other hemoglobins (ΔH° = - 9.3 kcal. for hagfish hemoglobin).2. Several aspects of Wald's (1952; see, also, Wald and Allen, 1957) theories on the evolution and function of hemoglobin are criticized in view of these data on hagfish hemoglobin and on the basis of information in the literature. It is concluded that: (1) At present there is no reason to favor cytochrome oxidase as the phylogenetic precursor of hemoglobin. (2) Many invertebrate hemoglobins function in oxygen transport. (3) If the i...