Comparison of the "mammal machine" and the "reptile machine": energy production

1981 ◽  
Vol 240 (1) ◽  
pp. R3-R9 ◽  
Author(s):  
P. L. Else ◽  
A. J. Hulbert
Keyword(s):  
Surface Area ◽  
Energy Production ◽  
Membrane Surface ◽  
Production Capacity ◽  
Volume Density ◽  
Internal Organs ◽  
Membrane Surface Area ◽  
Mitochondrial Volume ◽  
Mitochondrial Volume Density ◽  
The Difference

Standard metabolism and body composition were measured in Amphibolurus nuchalis and Mus musculus (a reptile and mammal with the same weight and body temperature). The metabolic capacity for energy production was assessed in liver, heart, brain, and kidney in the lizard and mouse by two methods: measurement of mitochondrial enzyme activity (cytochrome oxidase) and measurement of both mitochondrial volume density and membrane surface area. Both methods gave a three- to sixfold greater capacity for energy production in the mammal compared to the lizard which is less than the eightfold difference in their standard metabolisms. The difference in energy production capacity was not due to any single parameter but was a summation of several smaller differences. The mammal had relatively larger internal organs than the reptile, their organs had a greater proportion of mitochondria, and their mitochondria had a greater relative membrane surface area. These differences, it is suggested, may be due in part to different thyroid function in reptiles and mammals.

Mammals: an allometric study of metabolism at tissue and mitochondrial level

1985 ◽  
Vol 248 (4) ◽  
pp. R415-R421 ◽  
Author(s):  
P. L. Else ◽  
A. J. Hulbert
Keyword(s):  
Skeletal Muscle ◽  
Surface Area ◽  
Mitochondrial Membrane ◽  
Membrane Surface ◽  
Standard Metabolic Rate ◽  
Volume Density ◽  
Allometric Equation ◽  
Membrane Surface Area ◽  
Mitochondrial Volume ◽  
Mitochondrial Volume Density

Body composition, mitochondrial volume density, and mitochondrial membrane surface area were measured in six species of mammals representing a 100-fold weight range (18-2,067 g). The mammals examined included three eutherian species, two marsupial, and one monotreme species. The tissues examined were liver, kidney, brain, lung, heart, and skeletal muscle (gastrocnemius). Allometric equations were derived for tissue weight, and the allometric exponents ranged from 0.69 (brain) to 1.01 (skeletal muscle). Allometric relationships for mitochondrial membrane surface area were also determined both per milliliter tissue and per total tissue. Small mammals had a higher mitochondrial membrane surface area per milliliter tissue than large mammals in all tissues examined. These differences were significant in liver, kidney, brain, and heart. Total mitochondrial membrane surface area per tissue had allometric exponents ranging from 0.55 (kidney) to 0.78 (skeletal muscle). When total mitochondrial membrane surface area was summated for the major internal organs examined (liver, kidney, heart, and brain), the allometric equation was mitochondrial membrane surface area (m2) = 3.04 body wt0.59 (g). This was similar to the exponent of standard metabolic rate against body weight in the species examined (i.e., 0.62). The inclusion of skeletal muscle and lung into the summated mitochondrial membrane surface area increased the exponent to 0.76. This is compared with the relationship between maximal O2 consumption and body size in mammals.

Capillary and mitochondrial unit in muscles of a large lizard

1989 ◽  
Vol 256 (4) ◽  
pp. R982-R988 ◽  
Author(s):  
K. E. Conley ◽  
K. A. Christian ◽  
H. Hoppeler ◽  
E. R. Weibel
Keyword(s):  
Surface Area ◽  
Mitochondrial Membrane ◽  
Membrane Surface ◽  
Oxidative Capacity ◽  
Volume Density ◽  
Inner Mitochondrial Membrane ◽  
Capillary Length ◽  
Membrane Surface Area ◽  
Functional Relationships ◽  
Mitochondrial Volume

We asked whether capillaries and mitochondria form a structural and functional unit in the musculature of the Cuban iguana (Cyclura nubila) similar to that found in mammals. We found a significant correlation between capillary length density [Jv(c, f)] and mitochondrial volume density [Vv(mt, f)] of the musculature with a slope that revealed that on average 3.5 km of capillaries were associated with each milliliter of mitochondria (vs. approximately 11 km/ml in mammals). These capillaries had a diameter of 9 microns (vs. 4.5 microns in mammals), and the mitochondria had a surface density of the inner membranes of 25 m2/ml (vs. 30-45 m2/ml in mammals). These dimensions resulted in ratios of capillary to mitochondrial volume (0.22 ml/ml) and capillary wall to mitochondrial membrane surface area (39 cm2/m2) that were similar in Cyclura to those found in mammals (approximately 0.18 ml/ml and 35-52 cm2/m2, respectively). Also in agreement with mammalian values were the average oxidative capacity of the mitochondria derived from maximum rate of O2 consumption (VO2max) during exercise at 37 degrees C and the inner mitochondrial membrane surface area [S(im)] of the musculature [VO2max/S(im) = 0.04 vs. 0.06-0.15 ml O2.m-2.min-1 in mammals]. These common structural and functional relationships support the notion that capillaries and mitochondria represent a similar fundamental unit in muscles of both Cyclura and mammals.

scholarly journals Oxidative capacity distribution in skeletal muscle fibers of the rat.

1994 ◽  
Vol 189 (1) ◽  
pp. 1-11 ◽  
Author(s):  
M Philippi ◽  
A H Sillau
Keyword(s):  
Muscle Fibers ◽  
Oxidative Capacity ◽  
Volume Density ◽  
The Other ◽  
Isolated Mitochondria ◽  
Interfibrillar Mitochondria ◽  
Mitochondrial Volume ◽  
Mitochondrial Volume Density ◽  
The Difference ◽  
Subsarcolemmal Mitochondria

To study the distribution of oxidative capacity in muscle fibers, mitochondrial volume density and the oxidative capacity of isolated mitochondria were evaluated. Mitochondria were isolated from the subsarcolemmal and interfibrillar areas of the soleus (a muscle largely made up of slow oxidative fibers) and the gastrocnemius medial head (a muscle largely made up of fast glycolytic fibers) of the rat, and their oxidative capacities were evaluated using NADH- and FADH-generating substrates. In the soleus muscle, the subsarcolemmal mitochondria showed a lower oxidative capacity than interfibrillar mitochondria when NADH-generating substrates were used. This difference was not observed when FADH-generating substrates were used. In the gastrocnemius, there were no differences in the oxidative capacity of the subsarcolemmal and the interfibrillar mitochondria. Additionally, citrate synthase activity was found to be lower in mitochondria isolated from the subsarcolemmal area of the soleus than in the other mitochondrial preparations. These findings indicate that the difference in oxidative capacity of the isolated mitochondria is not related to differences in the inner mitochondrial membranes. Mitochondrial volume density was evaluated using electron micrographs of the subsarcolemmal and interfibrillar areas of slow oxidative fibers from the soleus and fast glycolytic fibers from the gastrocnemius. In the slow oxidative fibers, mitochondrial volume density in the subsarcolemmal area was four times higher than in the interfibrillar area. In the fast glycolytic fibers, mitochondrial volume densities in the subsarcolemmal and interfibrillar areas did not differ from that of the interfibrillar area of the slow oxidative fibers. The oxidative capacity of the tissue, calculated by multiplying the mitochondrial oxidative capacities by the mitochondrial volume densities, was 2-4 times higher in the subsarcolemmal areas of the soleus fibers than in the other areas studied. This was true in spite of the fact that the oxidative capacity of the subsarcolemmal mitochondria of the slow oxidative fibers was lower than those of the other mitochondrial populations studied. These results indicate that the difference in oxidative capacity between slow oxidative fibers and fast glycolytic fibers is the result of the much greater mitochondrial volume density in the subsarcolemmal area of the slow oxidative fibers.

Low-temperature adaptation of oxidative energy production in cold-water fishes

1988 ◽  
Vol 66 (5) ◽  
pp. 1098-1104 ◽  
Author(s):  
J. F. Dunn
Keyword(s):  
Low Temperatures ◽  
Energy Production ◽  
Cold Water ◽  
Large Diameter ◽  
Fish Muscle ◽  
Volume Density ◽  
Temperature Adaptation ◽  
Diffusion Limitations ◽  
Mitochondrial Volume ◽  
Mitochondrial Volume Density

This paper addresses the possibility that oxidative energy production in fish muscle is limited by low temperatures. Data are used from species that seasonally acclimatize to low temperatures, and from animals that have adapted to low temperatures over an evolutionary period. It is likely that the inhibitory effect of declining temperatures on the potential rate of oxidative energy production is compensated for largely by increasing the volume of mitochondria in the cell (volume density). For fishes that acclimatize, this increase in mitochondrial volume density may offset diffusion limitations. This is less likely for species that have adapted to low temperatures, because these animals have also developed large-diameter muscle cells. It is suggested that the stimuli for increasing cellular mitochondrial volume density, be they diffusion limitations or catalytic limitations, have not totally been overcome by increased mitochondrial volume density. In addition, a further restriction is concurrently placed upon maximum rates of oxygen uptake by the cell because the increase in mitochondrial volume density occurs at the expense of myofibrillar volume. This has the effect of reducing the maximum rate at which ATP can be used by working muscle.

scholarly journals 145 President Oral Presentation Pick: Prenatal stress increases skeletal muscle mitochondrial volume density and function in yearling Brahman calves

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 120-121
Author(s):  
Chloey P Guy ◽  
Catherine L Wellman ◽  
David G Riley ◽  
Charles R Long ◽  
Ron D Randel ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Creatine Kinase ◽  
Muscle Damage ◽  
Prenatal Stress ◽  
Citrate Synthase ◽  
Volume Density ◽  
Assembly Factor ◽  
Mitochondrial Volume ◽  
Mitochondrial Volume Density ◽  
And Function

Abstract We previously determined that prenatal stress (PNS) differentially affected methylation of DNA from leukocytes of 28-d-old calves. Specifically, COX14 (cytochrome c oxidase (COX) assembly factor) and CKMT1B (mitochondrial creatine kinase U-type) were hypomethylated and COA5 (COX assembly factor 5), COX5A (COX subunit 5A), NRF1 (nuclear respiratory factor 1), and GSST1 (glutathione S-transferase theta-1) were hypermethylated in PNS compared to non-PNS calves (P ≤ 0.05). Our current objective was to test the hypothesis that PNS exhibit impaired mitochondrial function and greater oxidative stress than non-PNS calves. Blood and longissimus dorsi muscle samples were collected from yearling Brahman calves whose mothers were stressed by 2 h transportation at 60, 80, 100, 120, and 140 days of gestation (PNS; 8 bulls, 6 heifers) and non-PNS calves (4 bulls, 6 heifers). Serum was evaluated for the stress hormone, cortisol, and muscle damage marker, creatine kinase; muscle was analyzed for mitochondrial volume density and function by citrate synthase (CS) and COX activities, respectively, concentration of malondialdehyde, a lipid peroxidation marker, and activity of the antioxidant, superoxide dismutase (SOD). Data were analyzed using mixed linear models with treatment and sex as fixed effects. Serum cortisol was numerically higher in PNS than non-PNS calves but was not statistically different. Muscle CS and COX activities relative to protein were greater in PNS than non-PNS calves (P ≤ 0.03), but COX relative to CS activity was similar between groups. Activity of COX was greater in bulls than heifers (P = 0.03), but no other measure was affected by sex. All other measures were unaffected by PNS. Prenatal stress did not affect markers of muscle damage and oxidative stress in yearling Brahman calves at rest but mitochondrial volume density and function were greater in PNS calves. Acute stressors induce oxidative stress, so implications of differences in mitochondria in PNS calves following a stressor should be investigated.

The macrophage capacity for phagocytosis

1992 ◽  
Vol 101 (4) ◽  
pp. 907-913 ◽  
Author(s):  
G.J. Cannon ◽  
J.A. Swanson
Keyword(s):  
Surface Area ◽  
Membrane Surface ◽  
Fc Receptors ◽  
Phagocytic Capacity ◽  
Membrane Surface Area ◽  
Murine Bone Marrow ◽  
Latex Beads ◽  
Endocytic Compartments ◽  
Frustrated Phagocytosis

Murine bone marrow-derived macrophages, which measure 13.8 +/− 2.3 microns diameter in suspension, can ingest IgG-opsonized latex beads greater than 20 microns diameter. A precise assay has allowed the determination of the phagocytic capacity, and of physiological parameters that limit that capacity. Ingestion of beads larger than 15 microns diameter required IgG-opsonization, and took 30 minutes to reach completion. Despite the dependence on Fc-receptors for phagocytosis of larger beads, cells reached their limit before all cell surface Fc-receptors were occupied. The maximal membrane surface area after frustrated phagocytosis of opsonized coverslips was similar to the membrane surface area required to engulf particles at the limiting diameter, indicating that the capacity was independent of particle shape. Vacuolation of the lysosomal compartment with sucrose, which expanded endocytic compartments, lowered the phagocytic capacity. This decrease was reversed when sucrose vacuoles were collapsed by incubation of cells with invertase. These experiments indicate that the phagocytic capacity is limited by the amount of available membrane, rather than by the availability of Fc-receptors. The capacity was also reduced by depolymerization of cytoplasmic microtubules with nocodazole. Nocodazole did not affect the area of maximal cell spreading during frustrated phagocytosis, but did alter the shape of the spread cells. Thus, microtubules may coordinate cytoplasm for engulfment of the largest particles.

241 Skeletal Muscle Mitochondrial Capacities Are Impacted by Breed and Temperament in Young Angus and Brahman Steers

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 127-127
Author(s):  
Chloey P Guy ◽  
Lauren T Wesolowski ◽  
Audrey L Earnhardt ◽  
Dustin Law ◽  
Don A Neuendorff ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fixed Effects ◽  
Linear Models ◽  
Citrate Synthase ◽  
Volume Density ◽  
Skeletal Muscle Mitochondria ◽  
Mitochondrial Volume ◽  
Mitochondrial Volume Density ◽  
Brahman Steers ◽  
The Impact

Abstract Temperament impacts skeletal muscle mitochondria in Brahman heifers, but this has not been investigated in steers or between cattle breeds. We hypothesized mitochondrial measures would be greater in Angus than Brahman, temperamental than calm steers, and the trapezius (TRAP) than the longissimus thoracis (LT) muscle. Samples from calm (n = 13 per breed), intermediate (n = 12 per breed), and temperamental (n=13 per breed) Angus and Brahman steers (mean±SD 10.0±0.8 mo) were evaluated for mitochondrial enzyme activities via colorimetry. Calm and temperamental LT samples were evaluated for oxidative phosphorylation (P) and electron transfer (E) capacities by high-resolution respirometry. Data were analyzed using linear models with fixed effects of breed, muscle, temperament, and all interactions. Brahman tended to have greater mitochondrial volume density (citrate synthase activity; CS) than Angus (P = 0.08), while intrinsic (relative to CS) mitochondrial function (cytochrome c oxidase activity) was greater in Angus than Brahman (P = 0.001) and greater in TRAP than LT (P = 0.008). Angus exhibited greater integrative (per mg tissue) and intrinsic P with complex I (PCI), P with complexes I+II (PCI+II), maximum noncoupled E, and E with complex II (ECII; P ≤ 0.04) and tended to have greater intrinsic leak (P = 0.1) than Brahman. Contribution of PCI to total E was greater in Angus than Brahman (P = 0.01), while contribution of ECII to total E was greater in Brahman than Angus (P = 0.05). A trend for the interaction of breed and temperament (P = 0.07) indicated calm Angus had the greatest intrinsic ECII (P ≤ 0.03) while intrinsic ECII was similar between temperamental Angus and calm and temperamental Brahman. Integrative PCI+II and ECII, and the contribution of PCI and PCI+II to overall E tended to be greater in temperamental than calm steers (P ≤ 0.09), while intrinsic ECII tended to be greater in calm than temperamental steers (P = 0.07). The impact of these mitochondrial differences on meat quality measures remains to be determined.

scholarly journals Effect Of Surface Area Of Dialyzer Membrane On The Adequacy Of Haemodialysis

2012 ◽  
Vol 7 (2) ◽  
pp. 9-11 ◽  
Author(s):  
NS Chowdhury ◽  
FMM Islam ◽  
F Zafreen ◽  
BA Begum ◽  
N Sultana ◽  
...  
Keyword(s):  
Renal Disease ◽  
Surface Area ◽  
End Stage Renal Disease ◽  
Membrane Surface ◽  
Reduction Ratio ◽  
Urea Clearance ◽  
Membrane Surface Area ◽  
Stage Renal Disease ◽  
End Stage ◽  
Urea Reduction Ratio

Introduction: Patients with end stage renal disease require 12 hours of haemodialysis per week in three equal sessions (4 hours/day for 3 days/week). But the duration and frequency of treatment can be reduced by increasing the surface area of the dialyzer membrane. Methods: In this prospective study 40 patients of end stage renal disease receiving haemodialysis for more than six months were included to observe the effects of increment in the surface area of the dialyzer membrane on the adequacy of haemodialysis. Result: It was observed that 20 patients receiving haemodialysis on a dialyzer with membrane surface area of 1.2 m² did not have satisfactory solute clearance index. Urea reduction ratio was 45.9 ± 3.03 and fractional urea clearance (Kt/V) was 0.76 ± 0.09. On the other hand patients (20 cases) receiving haemodialysis on a dialyzer with membrane surface area of 1.3 m² had a urea reduction ratio 50.76± 5.16 and fractional urea clearance (Kt/V) 0.91 ± 0.16. All the patients of both groups received dialysis for 8 hours/week in two equal sessions (4 hours/day for 2 days/week). Statistically the increment was significant (p<0.001). Conclusion: This study reveals, adequacy of dialysis can be increased by increasing the surface area of the dialyzer membrane. So, considering the poor socioeconomic condition of Bangladesh and patients' convenience, a short duration, low cost dialysis regime can be tried by increasing the surface area of dialyzer membrane. DOI: http://dx.doi.org/10.3329/jafmc.v7i2.10387 JAFMC 2011; 7(2): 9-11

scholarly journals Mitochondrial Fragmentation and Dysfunction in Type IIx/IIb Diaphragm Muscle Fibers in 24-Month Old Fischer 344 Rats

2021 ◽  
Vol 12 ◽  
Author(s):  
Alyssa D. Brown ◽  
Leah A. Davis ◽  
Matthew J. Fogarty ◽  
Gary C. Sieck
Keyword(s):  
Muscle Fibers ◽  
Volume Density ◽  
Diaphragm Muscle ◽  
Type I ◽  
Mitochondrial Fragmentation ◽  
Fiber Volume ◽  
Respiratory Capacity ◽  
Dehydrogenase Reaction ◽  
Mitochondrial Volume ◽  
Mitochondrial Volume Density

Sarcopenia is characterized by muscle fiber atrophy and weakness, which may be associated with mitochondrial fragmentation and dysfunction. Mitochondrial remodeling and biogenesis in muscle fibers occurs in response to exercise and increased muscle activity. However, the adaptability mitochondria may decrease with age. The diaphragm muscle (DIAm) sustains breathing, via recruitment of fatigue-resistant type I and IIa fibers. More fatigable, type IIx/IIb DIAm fibers are infrequently recruited during airway protective and expulsive behaviors. DIAm sarcopenia is restricted to the atrophy of type IIx/IIb fibers, which impairs higher force airway protective and expulsive behaviors. The aerobic capacity to generate ATP within muscle fibers depends on the volume and intrinsic respiratory capacity of mitochondria. In the present study, mitochondria in type-identified DIAm fibers were labeled using MitoTracker Green and imaged in 3-D using confocal microscopy. Mitochondrial volume density was higher in type I and IIa DIAm fibers compared with type IIx/IIb fibers. Mitochondrial volume density did not change with age in type I and IIa fibers but was reduced in type IIx/IIb fibers in 24-month rats. Furthermore, mitochondria were more fragmented in type IIx/IIb compared with type I and IIa fibers, and worsened in 24-month rats. The maximum respiratory capacity of mitochondria in DIAm fibers was determined using a quantitative histochemical technique to measure the maximum velocity of the succinate dehydrogenase reaction (SDHmax). SDHmax per fiber volume was higher in type I and IIa DIAm fibers and did not change with age. In contrast, SDHmax per fiber volume decreased with age in type IIx/IIb DIAm fibers. There were two distinct clusters for SDHmax per fiber volume and mitochondrial volume density, one comprising type I and IIa fibers and the second comprising type IIx/IIb fibers. The separation of these clusters increased with aging. There was also a clear relation between SDHmax per mitochondrial volume and the extent of mitochondrial fragmentation. The results show that DIAm sarcopenia is restricted to type IIx/IIb DIAm fibers and related to reduced mitochondrial volume, mitochondrial fragmentation and reduced SDHmax per fiber volume.

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