Enzymatic and biochemical characterization of the avian glycogen body

Fink, Aaron S.; Hefferan, Patrick M.; Howell, R. Rodney

doi:10.1016/0305-0491(75)90082-6

Cited by 10 publications

(8 citation statements)

References 17 publications

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“…Many (but not all) found a reduction in glycogen in the liver without an accompanying loss within the glycogen body (as summarized in De Gennaro, 1982). Notably, enzymatic assays revealed no presence of glucose-6-phosphatase (Benzo et al, 1975;Fink et al 1975), which is an enzyme necessary for the conversion of glucose-6-phosphate to free glucose.…”

Section: The Glycogen Body As a Metabolic Repositorymentioning

confidence: 99%

“…Alternative metabolic roles have been posed for the glycogen body. These include that it secretes glycogen directly into cerebrospinal fluid (Azoitia et al, 1985); assists in lipid production, perhaps for myelination (Benzo et al, 1975); or that it provides lactate or pyruvate, rather than glycogen and glucose, as energy sources (Dezza et al, 1970;Fink et al 1975).…”

Section: The Glycogen Body As a Metabolic Repositorymentioning

confidence: 99%

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The balance hypothesis for the avian lumbosacral organ and an exploration of its morphological variation

Stanchak

French

Perkel

et al. 2020

Preprint

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Birds (Aves) exhibit exceptional and diverse locomotor behaviors, including the exquisite ability to balance on two feet. How birds so precisely control their movements may be partly explained by a set of intriguing modifications in their lower spine. These modifications are collectively known as the lumbosacral organ (LSO) and are found in the fused lumbosacral vertebrae called the synsacrum. They include a set of transverse canal-like recesses in the synsacrum that align with lateral lobes of the spinal cord, as well as a dorsal groove in the spinal cord that houses an egg-shaped glycogen body. Based on compelling but primarily observational data, the most recent functional hypotheses for the LSO consider it to be a secondary balance organ, in which the transverse canals are analogous to the semicircular canals of the inner ear. If correct, this hypothesis would reshape our understanding of avian locomotion, yet the LSO has been largely overlooked in the recent literature. Here, we review the current evidence for this hypothesis and then explore a possible relationship between the LSO and balance-intensive locomotor ecologies.Our comparative morphological dataset consists of micro-computed tomography (μ-CT) scans of synsacra from ecologically diverse species. We find that birds that perch tend to have more prominent transverse canals, suggesting that the LSO is useful for balance-intensive behaviors.We then identify the crucial outstanding questions about LSO structure and function. The LSO may be a key innovation that allows independent but coordinated motion of the head and the body, and a full understanding of its function and evolution will require multiple interdisciplinary research efforts. Jargon-FreeBirds have an uncanny ability to move their heads independently of their bodies. They can keep their heads remarkably still to focus on their prey while twisting in flight or perched on a bouncing branch. How are they able to do this? Like us, birds have balance organs in their inner ears that act like gyroscopes. Surprisingly, birds may have an additional balance organ known as the "lumbosacral organ" in their spine, right above their legs, which might help them sense the movement of their body separately from their head. This second balance organ may have played a very important role in bird evolution and how birds move, but it has seldom been considered in recent scientific studies. This intriguing hypothesis is based in part on a series of fluid-filled, canal-like recesses in the bone surrounding the spinal cord, which resemble the semicircular canals of the inner ear. We looked for evidence of these canal-like recesses in many different bird species, and we found it in every bird we examined. We also found that birds that perch often have deeper recesses than birds that do not perch, suggesting these canals help maintain balance. This paper presents those findings, reviews the existing research, and identifies some key questions that need to be asked to advance our understanding of this fascinating and ...

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Section: The Glycogen Body As a Metabolic Repositorymentioning

confidence: 99%

Section: The Glycogen Body As a Metabolic Repositorymentioning

confidence: 99%

The balance hypothesis for the avian lumbosacral organ and an exploration of its morphological variation

Stanchak

French

Perkel

et al. 2020

Preprint

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“…and from his brother O. W. The specimens were analyzed by the techniques previously described. (Fink et al, 1975). The results of analysis for enzyme content are shown in Table II.…”

Section: Quantitative Estimation Of Muscle Enzymes In Family Membersmentioning

confidence: 99%

“…After examination all family members received an ischemic lactate tolerance test and a muscle biopsy. Quantitative enzyme estimation was carried out on a fresh frozen specimen of muscle, using the method described by Fink et al (1975).…”

mentioning

confidence: 99%

Myophosphorylase Deficiency (McArdle's Disease): Report of a Family

Mahmud

Howell

Stevenson

et al. 1976

Can. j. neurol. sci.

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“…Note that the glycogen body is separated from the neural tissue proper (stippled) after adrenergic stimulation in vitro was reported by Lee et al (2001). As the glycogen body lacks glucose-6-phosphatase (Benzo et al 1975;Fink et al 1975), it is not a source of glucose. In vitro, glycogen body cells release lactate, which may serve as a source of energy (Dezza et al 1970).…”

Section: Introductionmentioning

confidence: 99%

The blood-brain barrier of the chick glycogen body (corpus gelatinosum) and its functional implications

Möller

Kummer

2003

Cell and Tissue Research

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Among recent vertebrates only birds possess a glycogen body (corpus gelatinosum), located in the rhomboidal sinus of the lumbosacral region of the spinal cord and separated from the neural tissue proper. Because of the specific topographical situation of this circumventricular organ, the structure of its vascular system is of special interest with respect to the still unsolved functional problems. The existence of a blood-brain barrier is demonstrated by the exclusion of intravascularly injected tracer (horseradish peroxidase), and immunocytochemical demonstration of glucose transporter-1 as a functional marker and of neurothelin, occludin and ZO-1 as structural markers. Alkaline phosphatase and gamma-glutamyltransferase activities, two enzyme reactions frequently used for demonstration of an established blood-brain barrier in vitro, were localized histochemically on the plasmalemma of glycogen body cells and were absent from the endothelium. In addition, local enlargements of the intercellular space were observed by transmission and scanning electron microscopy. In accordance with the concept of a third circulation the cerebrospinal fluid may be the vehicle for distributing substances originating in the glycogen body to the CNS, while the vascular endothelium maintains the internal milieu by virtue of its dynamic barrier functions.

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Enzymatic and biochemical characterization of the avian glycogen body

Cited by 10 publications

References 17 publications

The balance hypothesis for the avian lumbosacral organ and an exploration of its morphological variation

The balance hypothesis for the avian lumbosacral organ and an exploration of its morphological variation

Myophosphorylase Deficiency (McArdle's Disease): Report of a Family

The blood-brain barrier of the chick glycogen body (corpus gelatinosum) and its functional implications

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