Occurrence of root effect hemoglobinsin Amazonian fishes

Farmer, Martha; Fyhn, Hans Jørgen; Fyhn, Unni E. H.; Noble, Robert W.

doi:10.1016/s0300-9629(79)80005-5

Cited by 77 publications

(21 citation statements)

References 36 publications

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“…Helcogrumma also possesses a Root effect, although as with the case for some other species lacking a swim bladder, the Root shift may operate through the choroid rete mirabile to generate high ocular pressures. A Root effect is also present in several bimodal airbreathing fishes (Farmer et al 1979) and in species such as eels, catfish and tenth which thrive in water with reduced PO, (Albers et al 1981, Breepoel et al 1981, Jensen & Weber 1982 though not in others such as the blackfish (Cech et al 1979). It is interesting in this respect that in common with Helcogramma, both eels (Berg & Steen 1965) and catfish (Hughes & Singh 1971) have reduced v02 during air breathing.…”

Section: Discussionmentioning

confidence: 98%

Respiration and oxygen transport functions of the blood from an intertidal fish, Helcogramma medium (Tripterygiidae)

Innes

Wells

1985

Environ Biol Fish

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Aquatic and aerial oxygen uptake (VO,), ventilation frequency, and oxygen transport properties of the blood were determined for the intertidal fish Helcogramma medium. Ventilation frequency increased in response to decreased environmental PO, and aquatic VOZ was maintained down to a critical PO, of 30-40 mm Hg. Below PO, = 30mmHg fish intermittently gulped air and finally emerged into air at PO, = 18mm Hg. After 1 h exposure to air V02 decreased to 60% of the aquatic rate and this was accompanied by an increase in blood lactate. Aerobic expansibility was reduced in air (~1.2) compared to water (x5.5). The Hb concentration was 0.47 + 0.13mmoll-' and hematocrit 11.55 IfI 3.61% indicating a moderate O,-carrying capacity. Oxygen affinity was not especially high (P,,, = 19 mm Hg at pH 7.7 and 1S'C) and ATP was the predominant acid-soluble phosphate regulating P,,,. The equilibrium curve was essentially hyperbolic (Hill's y1= 1.2) with a marked Bohr effect (@ = -1.06) and Root effect (saturation depressed by 50% at pH7.1). The pattern of respiration and the respiratory properties of the blood together with observations of the behaviour of the fish during aerial exposure indicated that Helcogramma is adapted to living in a well-aerated environment yet can adequately tolerate short term exposure to low aquatic PO, or air.

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Section: Discussionmentioning

confidence: 98%

Respiration and oxygen transport functions of the blood from an intertidal fish, Helcogramma medium (Tripterygiidae)

Innes

Wells

1985

Environ Biol Fish

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“…The Root effect was performed as described by Farmer et al (1979) and the data were divided into four arbitrary categories based on approximate percentages: 0, less than 10% deoxygenation; +, 10%-20% deoxygenation; ++, 20%-40% deoxygenation; +++, more than 40% deoxygenation. The amount of GTP and ATP used in these experiments was calculated as described above for GTP.…”

Section: Methodsmentioning

confidence: 99%

Astyanax scabripinnis (Pisces: Characidae) hemoglobins: structure and function

Landini¹,

Schwantes²,

Schwantes³

2002

Braz. J. Biol.

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Electrophoretic patterns of hemoglobins, Root effect, Bohr effect in blood and stripped hemoglobin, Hb-O 2 affinity GTP modulation of Astyanax scabripinnis (lambari), caught at three different altitudes in Ribeirão Grande, near Campos do Jordão (São Paulo), are described. All populations showed the same electrophoretic patterns: two cathodal components in starch gel. Normal Bohr effect values were found in these three populations both in blood (φ = -0,11) and stripped hemoglobin (φ = -0,12). Different blood O 2 affinities collected in fish of these 3 populations were detected. GTP has a large influence on Hb-O 2 binding properties in A. scabripinnis. Stripped hemoglobin shows small Root effect. The addition of triphosphated nucleotides increases this effect. GTP is more effective than ATP on enhancing Root effect. Oxygen availability in water can be the factor responsible for differences found in blood O 2 affinity.Key words: lambari, oxygen availability, organic phosphates, Bohr effect, altitude. RESUMOHemoglobinas de Astyanax sacabripinis (Pisces: Characidae): estrutura e função Padrão eletroforético de hemoglobina, efeito Root, efeito Bohr em sangue e em Hb stripped e efeito do GTP na afinidade Hb-O 2 de Astyanax scabripinnis (lambari) coletados em três altitudes diferentes no Ribeirão Grande, na região de Campos do Jordão (São Paulo), são descritos. Todas as populações mostraram os mesmos padrões eletroforéticos: dois componentes catódicos em gel de amido. Efeito Bohr normal foi encontrado para as três populações, tanto em sangue (φ = -0,11) quanto em Hb stripped (φ = -0,12). Detectamos afinidades diferentes da hemoglobina ao O 2 entre as três populações estudadas. GTP possui forte influência nas propriedades de ligação da hemoglobina ao oxigênio em Astyanax scabripinnis. Em hemoglobina stripped, o efeito Root é baixo. A adição de nucleotídeos trifosfatados aumenta esse efeito. GTP é mais efetivo que ATP no aumento desse efeito. A disponibilidade de O 2 na água pode ser o fator responsável pelas diferenças encontradas nas afinidades da hemoglobina pelo oxigênio.Palavras-chave: lambari, disponibilidade de oxigênio, fosfato orgânico, efeito Bohr, altitude.

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“…This notion is supported by the in vitro demonstration of reduced O 2 -carrying capacity of Hb at low pH and high P O 2 (Root, 1931;Root and Irving, 1943;Scholander and van Dam, 1954;Hamann, 1990;Pelster and Weber, 1990), the pattern of distribution of the Root effect almost exclusively to teleost fish with swimbladder gas secretion and high P O 2 values in the eye (Farmer et al, 1979;Pelster and Weber, 1991;Pelster and Randall, 1998), the evolutionary co-development of certain morphological and physiological traits deemed essential for gas secretion (Berenbrink et al, 2005), and by the observation of higher venous than arterial P O 2 values in the eel gas gland (Steen, 1963;Kobayashi et al, 1990). All these data, however, represent indirect evidence; direct confirmation of the postulated chain of mechanisms is still lacking.…”

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confidence: 88%

Oxygen delivery to the fish eye: Root effect as crucial factor for elevated retinalPO2

Waser

Heisler

2005

Journal of Experimental Biology

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SUMMARY Although the retina has one of the highest metabolic rates among tissues,certain teleost fishes lack any vascular supply to this organ which, in combination with the overall thickness of the organ, results in extremely long diffusion distances. As the only way to compensate for these obstacles, oxygen partial pressure (PO2) in the eyes of such fish is elevated far above atmospheric values. Although not supported by any direct evidence, the enhancement of PO2 is considered to be related to the Root effect, the release upon acidification of Hb-bound O2 into physical dissolution, possibly supported by counter-current multiplication similar to the loop of Henle. The present study evaluates the magnitude of intraocular PO2 enhancement under tightly controlled physiological conditions, to directly confirm the involvement of the Root effect on intraocular PO2 in the retina of rainbow trout Oncorhynchus mykiss. Intraocular PO2 was determined with special polarographic microelectrodes inserted into the eye. PO2profiles established in vivo by driving electrodes through the entire retina yielded average PO2 values between 10 mmHg (1.3 kPa) at the inner retinal surface and 382 mmHg (50.9 kPa) close to the outer retinal limit (Bruch's membrane). According to estimates on the basis of the diffusion distances determined from sections of the retina(∼436 μm at the site of PO2 measurement)and literature data on specific oxygen consumption, the in vivodetermined values would be sufficient to cover the oxygen demand of the retina with some safety margin. For a clear and direct in-tissue-test as to the involvement of the Root effect, an isolated in vitro eye preparation was established in order to avoid the problem of indirect blood supply to the eye from the dorsal aorta only via the pseudobranch, a hemibranch thought to modulate blood composition before entry of the eye. Any humoral effects (e.g. catecholamines)were eliminated by perfusing isolated eyes successively with standardized red blood cell (RBC) suspensions in Ringer, using trout (with Root) and human(lacking any Root effect) RBC suspension. To optimize perfusate conditions for maximal Root effect, the Root effect of trout RBCs was determined in vitro via graded acidification of individual samples equilibrated with standardized gas mixtures. During perfusion with trout RBC, PO2 at the outer retinal limit was 99 mmHg(13.2 kPa), but fell by a factor of 3.3 upon perfusion with human RBC in spite of higher total oxygen content (TO2 2.8 for trout vs 3.9 mmol l-1 for human RBC). Upon reperfusion with trout RBC, PO2 was restored immediately to the original value. This regularly observed pattern indicated a highly significant difference (P=0.003) between perfusion with trout (with Root effect;high retinal PO2) and perfusion with human (no Root effect; low retinal PO2) RBC suspension,thus clearly demonstrating that the Root effect is directly involved and a crucial prerequisite for the enhancement of PO2in the retina of the teleost eye.

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Occurrence of root effect hemoglobinsin Amazonian fishes

Cited by 77 publications

References 36 publications

Respiration and oxygen transport functions of the blood from an intertidal fish, Helcogramma medium (Tripterygiidae)

Respiration and oxygen transport functions of the blood from an intertidal fish, Helcogramma medium (Tripterygiidae)

Astyanax scabripinnis (Pisces: Characidae) hemoglobins: structure and function

Oxygen delivery to the fish eye: Root effect as crucial factor for elevated retinalPO2

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