The effects of metabolic inhibitors on the contraction of creatine-depleted muscle

1982 ◽  
Vol 60 (2) ◽  
pp. 114-119 ◽  
Author(s):  
G. W. Mainwood ◽  
M. Alward ◽  
B. Eiselt
Keyword(s):  
Creatine Phosphate ◽  
Diaphragm Muscle ◽  
Metabolic Inhibitors ◽  
Energetic Cost ◽  
Energy Reserves ◽  
Similar Extent ◽  
Additional Energy ◽  
Energy Stores ◽  
Wet Weight ◽  
The Mean

Rats were fed on a diet containing 1% β-guanidinopropionate (Gp) to deplete their muscles of creatine. The apparent energy reserves (creatine phosphate (CrP) + ATP) of rested state diaphragm muscle strips were found to be 79% depleted by this treatment. To determine if the effective energy reserves for contraction were depleted to a similar extent, the response to direct electrical stimulation (0.2-s tetani) was measured in the presence of inhibitors of respiration (NaCN) and glycolysis (iodoacetate). Only 4 ± 1 contractions could be elicited from strips from Gp-fed animals. Normal strips gave 15 ± 2 contractions under the same conditions. For both sets of diaphragms the energetic cost of contraction in terms of ~P was approximately 1 μmol/g wet weight. The mean level of Pi generated following stimulation to exhaustion was 10.1 μmol/g more in normal than in depleted strips. It is concluded that no significant additional energy stores such as phosphorylated Gp are readily available for contraction in muscles depleted of creatine by Gp treatment.

Localization of calcium and zinc in the sperm storage tubules of chicken, quail and turkey using X-ray microanalysis

Reproduction ◽  
2000 ◽  
pp. 331-336 ◽  
Author(s):  
L Holm ◽  
H Ekwall ◽  
GJ Wishart ◽  
Y Ridderstrale
Keyword(s):  
Calcium Concentration ◽  
Sperm Storage ◽  
X Ray ◽  
Elemental Concentrations ◽  
Low Concentrations ◽  
Intracellular Content ◽  
Wet Weight ◽  
The Mean ◽  
Sperm Storage Tubules ◽  
Scanning Electron

Sperm storage tubules from the utero-vaginal junction of chickens, quails and turkeys were analysed for calcium and zinc using X-ray microanalysis of ultra-rapidly frozen tissue in a scanning electron microscope. This technique enabled the tubular fluid surrounding the stored spermatozoa and the intracellular content of the cells of the sperm storage tubules to be analysed separately and, by using standards with known concentrations, their elemental concentrations were estimated. The mean (+/- SEM) concentration of calcium in the tubular fluid from chickens, quails and turkeys was 17 +/- 3, 19 +/- 3 and 17 +/- 4 mmol kg(-1) wet weight, respectively. The intracellular calcium concentration of the cells of the tubules did not differ significantly from these values and was also similar in the mucosal epithelial cells of the utero-vaginal junction. Zinc was localized in the cells of turkey sperm storage tubules and tubular fluid, but at low concentrations. No zinc could be detected in corresponding structures from chickens and quails. The concentration of calcium in the tubular fluid is within the range known to inhibit the motility of spermatozoa, supporting this function for calcium during storage. Zinc is known to depress turkey sperm metabolism and it may also be involved in inducing quiescence of spermatozoa during storage in this species.

scholarly journals Energy Stores, Oxidative Balance, and Sleep in Migratory Garden Warblers (Sylvia borin) and Whitethroats (Sylvia communis) at a Spring Stopover Site

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Andrea Ferretti ◽  
Scott R McWilliams ◽  
Niels C Rattenborg ◽  
Ivan Maggini ◽  
Massimiliano Cardinale ◽  
...  
Keyword(s):  
Food Intake ◽  
High Energy ◽  
Oxidative Status ◽  
Energy Reserves ◽  
Stopover Site ◽  
Garden Warbler ◽  
Oxidative Balance ◽  
Energy Stores ◽  
Sylvia Borin ◽  
Sylvia Communis

Synopsis Little is known about how songbirds modulate sleep during migratory periods. Due to the alternation of nocturnal endurance flights and diurnal refueling stopovers, sleep is likely to be a major constraint for many migratory passerine species. Sleep may help to increase the endogenous antioxidant capacity that counteracts free radicals produced during endurance flight and reduces energy expenditure. Here, we investigated the relationship between sleep behavior, food intake, and two markers of physiological condition—the amount of energy reserves and oxidative status—in two migratory songbird species, the garden warbler (Sylvia borin) and the whitethroat (Sylvia communis). In garden warblers, birds with high energy stores were more prone to sleep during the day, while this condition-dependent sleep pattern was not present in whitethroats. In both species, birds with low energy stores were more likely to sleep with their head tucked in the feathers during nocturnal sleep. Moreover, we found a positive correlation between food intake and the extent of energy reserves in garden warblers, but not in whitethroats. Finally, we did not find significant correlations between oxidative status and sleep, or oxidative status and energy stores. Despite our study was not comparative, it suggests that different species might use different strategies to manage their energy during stopover and, additionally, it raises the possibility that migrants have evolved physiological adaptations to deal with oxidative damage produced during migration.

Cadmium concentrations in kidneys of sheep and cattle in Western Australia. 1. Regional distribution

1994 ◽  
Vol 45 (4) ◽  
pp. 851 ◽  
Author(s):  
PW Morcombe ◽  
DS Petterson ◽  
HG Masters ◽  
PJ Ross ◽  
JR Edwards
Keyword(s):  
Western Australia ◽  
Geometric Mean ◽  
Regional Distribution ◽  
Adult Cattle ◽  
Agricultural Region ◽  
Wet Weight ◽  
The Mean ◽  
Winter Annual ◽  
Rate Of Accumulation ◽  
Cattle And Sheep

A sample of 4973 kidneys from sheep stratified by age and shire of origin within the Agricultural Region of Western Australia, was analysed for cadmium (Cd) content during the period August 1989 to April 1991. The geometric mean Cd concentration in the kidney of hogget ewes was 0.9 mg/kg, in 4-tooth ewes 1.47 mg/kg and in adult ewes 3.34 mg/kg on a wet weight basis. The mean Cd concentrations of either ewe or hogget flocks from different Divisions of the Agricultural Region did not differ from each other. The annual increase in Cd concentration of kidney from hogget sheep was estimated to be 0-65 mg/kg. The rate of accumulation of Cd in kidney from cattle and sheep grazing the same properties was similar. Kidneys from a sample of 354 adult cattle from the Kimberley Region and 483 aged sheep from the Pastoral Region, both areas of unimproved rangelands, had geometric mean Cd concentrations of 0.15 mg/kg and 0-31 mg/kg respectively. A higher Cd concentration in flocks from the divisions adjacent to the Agricultural Region may have resulted from the establishment of some volunteer species of winter annual pastures in the rangeland.

Normal levels of vitamin A in tissues of the Syrian hamster (Mesocricetus auratus) determined colorimetrically

1988 ◽  
Vol 22 (2) ◽  
pp. 117-121 ◽  
Author(s):  
M. E. Robinson ◽  
A. M. Verrinder Gibbins ◽  
M. H. Hardy
Keyword(s):  
Vitamin A ◽  
Syrian Hamster ◽  
Cheek Pouch ◽  
Standard Diet ◽  
Male And Female ◽  
Mean Values ◽  
A Value ◽  
Significant Difference ◽  
Wet Weight ◽  
The Mean

Vitamin A levels in tissues of 20 normal adult hamsters on a standard diet were measured colorimetrically. No significant difference between male and female animals was found for any of the tissues sampled. The mean vitamin A value for blood plasma in 20 animals was 53·4 μg/dl. Mean values for liver, kidneys, flank skin and cheek pouch were 813, 1·29, 1·84 and 1·31 mg/g wet weight, respectively. The vitamin assay was less suitable for small organs such as trachea.

THE EFFECT OF INGESTED CHLORTETRACYCLINE ON SOME HYDROLASES AND ORGANS ASSOCIATED WITH THE DIGESTIVE PROCESS IN GROWING PIGS: II. PROTEASE, AMYLASE, AND GELLULASE ACTIVITY OF THE CONTENTS OF THE SMALL INTESTINE AND OF THE CECUM; WEIGHTS OF SMALL INTESTINE AND MUCOSA

1957 ◽  
Vol 35 (3) ◽  
pp. 195-202 ◽  
Author(s):  
M. A. A. Vonk ◽  
L. W. McElroy ◽  
R. T. Berg
Keyword(s):  
Small Intestine ◽  
Dry Matter ◽  
Cellulase Activity ◽  
Dry Weight ◽  
Growing Pigs ◽  
Weanling Pigs ◽  
Intestinal Contents ◽  
Wet Weight ◽  
The Mean ◽  
Ad Libitum

Four treatments, involving differences in method of feeding and interval between last feed and slaughter, were employed in a study of the effect of dietary chlortetracycline on protease, amylase, and cellulase activity in the intestinal and cecal contents of 16 pairs of weanling pigs. Most consistent results were obtained with six pairs which were limited pair-fed except for the final feeding during which feed was available ad libitum for a 4-hour period ending 18 hours before slaughter. The mean total activities of all three hydrolases in the contents of the small intestines and of the ceca of the antibiotic-fed animals of these six pairs were significantly greater than in those of the control animals. Expressed as activity per gram dry matter of intestinal contents, significantly higher values for protease and amylase, but not for cellulase, were observed in the pigs that had received chlortetracycline. When the combined results obtained from all 16 pairs of the experimental animals were analyzed, the results showed that on a basis of activity per gram dry matter of intestinal contents, ingested chlortetracycline was associated with significant increases in amylase and cellulase but not in protease activity. Protease, amylase, and cellulase activities per gram dry matter of cecal contents were higher for pigs fed the antibiotic than for their controls. The mean wet weight of the empty small intestine and the mean dry weight of the mucosa scraped from the anterior 3-meter section of the small intestine were lower for the chlortetracycline-fed animals, but the differences were not statistically significant.

Month of harvest and yield components of tea tree. II. Oil concentration, composition, and yield

1996 ◽  
Vol 47 (5) ◽  
pp. 817 ◽  
Author(s):  
GJ Murtagh ◽  
GR Smith
Keyword(s):  
Biomass Yield ◽  
Significant Loss ◽  
Oil Yield ◽  
Energy Reserves ◽  
Tea Tree ◽  
Air Temperatures ◽  
Oil Concentration ◽  
Biomass Yields ◽  
The Mean ◽  
High Concentrations

Changes in the concentration, composition, and yield of oil in coppice growth of tea tree (Melaleuca alternzfolia) were assessed when plants were harvested in different months. Oil concentrations in leaves were lower when plants were harvested in July-September than in other months, but biomass yields were higher. Consequently, there was no consistent effect of harvest month on oil yield. Oil yield varied as much between the same month in different years, as between months within a year. The oil concentration in one harvest was positively related to the biomass yield at the previous harvest of the same plants, suggesting that a carryover of energy reserves contributed to oil production. The oil concentration was also positively related to the mean air temperatures over the 3 months before harvest. The proportion of the economically significant compounds in oil, terpinen-4-01 and 1,8-cineole, was not affected by either the month of harvest or regrowth cycle, but other compounds did change. There was a significant loss of monoterpene olefins from oil which was present at high concentrations.

Seasonal and Geographic Variation in the Species Composition and Size of Prey Consumed by Grey Seals (Halichoerus grypus) on the Scotian Shelf

1993 ◽  
Vol 50 (8) ◽  
pp. 1768-1778 ◽  
Author(s):  
W. D. Bowen ◽  
J. W. Lawson ◽  
B. Beck
Keyword(s):  
Atlantic Cod ◽  
Halichoerus Grypus ◽  
Scotian Shelf ◽  
Sand Lance ◽  
Atlantic Mackerel ◽  
Relative Contribution ◽  
Wet Weight ◽  
The Mean ◽  
Silver Hake ◽  
Commercial Size

The grey seal (Halichoerus grypus) population on the Scotian Shelf has grown significantly over the past 20 yr, thus increasing the potential for competitive interactions between grey seals and fisheries. The relative contribution (percent wet weight) and size of prey eaten were estimated from otoliths and squid beaks recovered from 143 stomachs that contained food of the 528 collected from 1988 to 1990. Although 22 taxa were found, only four species (Atlantic herring, silver hake, Atlantic cod, and squid) accounted for 80% of the estimated weight of food eaten. The mean length of prey eaten ranged from 19 to 35 cm for six species. Only 17% of the cod and none of the pollock and squid eaten were of the length taken in commercial fisheries. However, about 80% of the silver hake and herring eaten were of commercial size. Offshore at Sable Island, northern sand lance, silver hake, and squid (in order of importance) accounted for 86.1% of the wet weight ingested by seals during summer; sand lance and cod accounted for 96.1% of prey eaten in winter. At inshore locations, herring, cod, and pollock made up 90% of the diet in summer; Atlantic mackerel, cod, squid, and herring made up 83% of the diet in winter.

Background Levels and Radiation Dose Yield of o-Tyrosine in Chicken Meat

1991 ◽  
Vol 54 (12) ◽  
pp. 935-938 ◽  
Author(s):  
NOEMI CHUAQUI-OFFERMANNS ◽  
TOM MCDOUGALL
Keyword(s):  
Radiation Dose ◽  
Dose Response ◽  
Response Curve ◽  
Dose Range ◽  
Background Level ◽  
Chicken Meat ◽  
Dose Response Curve ◽  
Poultry Meat ◽  
Wet Weight ◽  
The Mean

The measurement of o-tyrosine levels in poultry meat is a potential method for postirradiation dosimetry of poultry. The validity of using o-tyrosine for this purpose has not yet been established. As part of the validation process, the o-tyrosine content in unirradiated chicken meat, the radiation dose response curve, and the effects of postirradiation storage on o-tyrosine levels are examined. In 18 individual samples, the mean background level of o-tyrosine was 0.18 ± 0.11 ppm (wet weight, 70% moisture), and the most frequent background level (60% of the cases) was between 0.05 and 0.15 ppm (wet weight, 70% moisture). In pooled samples of 10 chickens, the mean background level was 0.12 ± 0.03 ppm (wet weight, 70% moisture). The levels were not significantly affected by storage at 5°C (7 d) or by freezing the sample. The radiation dose response curve was linear within the dose range studied (0 to 10 kGy), with a slope of 0.127 ± 0.003 ppm (wet weight)/kGy. Although there was some variation in the intercept (0.132 ± 0.013), the slope was the same in all samples tested. Postirradiation storage at either 4 or 8°C until spoilage did not affect the levels of o-tyrosine. These data indicate that o-tyrosine level may be useful for determining the absorbed dose in chicken meat gamma-irradiated to doses greater than 0.6 kGy. Further validation studies are continuing.

Active transport of potassium by heart mitochondria

1960 ◽  
Vol 198 (4) ◽  
pp. 847-854 ◽  
Author(s):  
Frank Ulrich
Keyword(s):  
Methylene Blue ◽  
Active Transport ◽  
Creatine Phosphate ◽  
Rabbit Heart ◽  
Potassium Transport ◽  
Heart Mitochondria ◽  
Metabolic Inhibitors ◽  
Mitochondrial Suspension ◽  
High Concentrations ◽  
Potassium Gradient

Rabbit heart mitochondria contained potassium which could not be removed with four washings of isotonic sucrose or sodium chloride at 0–4°C. Aging, increasing concentrations of potassium, and a number of metabolic poisons either partially or completely inhibited the active transport of potassium into heart mitochondria when these particles were incubated for 15 minutes in air at 37.4° in a medium to which alpha-ketoglutarate and AMP or ATP had been added. Compounds uncoupling oxidative phosphorylation—such as arsenite, 2,4-dinitrophenol, l-thyroxine, calcium chloride, dicumarol, pentachlorophenol and methylene blue—inhibited potassium transport but usually only at relatively high concentrations (10–3 m). With the exception of p-chloromercuribenzoate, neither aging nor metabolic inhibitors prevented the extrusion of water by the mitochondria in the presence of alpha-ketoglutarate and AMP or ATP. Although addition of either ATP or substrate alone to the mitochondrial suspension resulted in a significant increase in the potassium gradient, the latter was much greater when both substrate and ATP (or ADP or AMP) were added together. ADP or AMP alone caused a very slight but probably not significant increase in the potassium gradient and creatine phosphate had no effect.

The Hawk–Dove game as an average-cost problem

1991 ◽  
Vol 23 (04) ◽  
pp. 667-682
Author(s):  
J. M. McNamara ◽  
S. Merad ◽  
E. J. Collins
Keyword(s):  
Average Cost ◽  
Transition Probabilities ◽  
Energy Reserves ◽  
Stationary Policy ◽  
Evolutionarily Stable Strategies ◽  
Cost Criterion ◽  
Single Animal ◽  
The Mean ◽  
Evolutionarily Stable ◽  
Limiting Value

This paper considers a version of the Hawk–Dove game of Maynard Smith and Price (1973) in which animals compete for a sequence of food items. Actions may depend on an animal's energy reserves. Costs and transition probabilities under a given policy depend on the mean level of aggressiveness, p, of the rest of the population. We find the optimal policy for a single animal under an average cost criterion when ρ is constant over time. We then consider the whole interacting population when individual members follow the same stationary policy. It is shown that the mean aggressiveness, p, asymptotically approaches a limiting value in this population. We then consider the existence of evolutionarily stable strategies for the population. It is shown that such strategies always exist but may not be unique.

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