首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
  • 1.1. Some effects of restricting feed intake for 96 or 168 hr were determined in male Nubian goats.
  • 2.2. Goats restricted for 96 hr lost 11.6% of their body weight, and goats restricted for 168 hr lost 19.8%.
  • 3.3. Feed restriction for up to 168 hr did not produce significant effects on the heart rate, respiratory rate or rectal temperature.
  • 4.4. Haemoglobin concentration, packed cell volume and erythrocyte number were all decreased by feed restriction. There was also a tendency towards eosinopenia and lymphopenia.
  • 5.5. Feed restriction for 96 or 168 hr raised the plasma activity of aspartate transaminase, and did not affect significantly cholinesterase activity. Plasma amine oxidase activity was significantly reduced in goats restricted for 168 hr.
  • 6.6. Feed restriction produced significant increases in the blood or plasma concentrations of lactate. pyruvate, non-esterified fatty acids, cholesterol, ketone bodies and bilirubin.
  • 7.7. Significant decreases were found in the concentrations of total protein and calcium.
  • 8.8. No significant changes were observed in the plasma concentrations of glucose, sodium or potassium.
  相似文献   

2.
  • 1.1. Seasonal variation in total lipids was examined in several body components of the turtle Sternotherus odoratus.
  • 2.2. Carcass fat stores in both sexes were depleted during winter. Additionally, a decline in carcass lipids was associated with increases in gonadal mass.
  • 3.3. Concentrations of liver lipids were maximal during August and minimal during winter.
  • 4.4. Males showed little seasonal change in plasma lipid levels, whereas females had seasonal peaks temporally associated with ovarian development and carcass fat storage.
  • 5.5. Ovarian concentrations of lipids were minimal after nesting and increased during fall.
  • 6.6. Results suggest that S. odoratus uses stored fats both for reproduction and maintenance during winter.
  相似文献   

3.
  • 1.1. Fundamental chitin digestion characteristics of Crassostrea virginica crystalline style were investigated.
  • 2.2. Optimum temperature and pH were 34°C and 4.8. respectively.
  • 3.3. The colloidal regenerated chitin (0.56mol/0.5 ml: GlcNAc equivalents) was saturating under all enzyme levels encountered.
  • 4.4. There was no evidence of end product inhibition, even after 100 hr incubation.
  • 5.5. Calculated Km for the chitinase complex was 1.19mM when determined using a 30 min assay, but was only 0.70 mM when determined using a 4.6 hr assay.
  • 6.6. Both Km values are lower than reported for similar assays in other molluscs and for most bacteria.
  • 7.7. Effect of substrate preparation on the kinetics are discussed.
  • 8.8. Eight peaks of chitinase activity were resolved by DEAE-Fractogel ion exchange chromatography.
  相似文献   

4.
  • 1.1. In late winter, oxygen consumption of honey bee (Apis mellifera L.) clusters showed marked 24-hr periodicity, even when held under constant temperature conditions.
  • 2.2. Minimal rates of metabolism (as low as 3.4 w kg −1) were usually reached at night (ca. 0500 hr), and maximum rates (as high as 33.5 w kg−1) in midday (ca. 1400 hr).
  • 3.3. Colonies with brood showed less excursion in daily metabolic rate, by maintaining higher night-time levels.
  • 4.4. There is a pronounced decrease in metabolic rate for the intact cluster of 9480–23,394 bees from the rates reported for individuals or small groups of bees.
  相似文献   

5.
  • 1.1. The mechanism of action of glyburide (a sulfonylurea) on muscle has been investigated by measuring glucose uptake and glucose transporter (GLUT4) protein levels after chronic glyburide treatment.
  • 2.2. A dietary induced insulin resistant rat model (4 wk of high-fat, high-sucrose feeding) was given glyburide (2mg/kg/day) for 10 days and glucose uptake was measured in a perfused hindquarter preparation.
  • 3.3. Protein levels of the GLUT4 glucose transporter were determined by Western analysis.
  • 4.4. After 7 days of treatment, rats fed glyburide had lower blood glucose concentrations 2 hr (72 ± 5 vs 103 ± 12 mg/dl) and 24 hr (97 ± 7 vs 123 ± 7 mg/dl) after glyburide administration with no difference in serum insulin levels compared to vehicle treated animals.
  • 5.5. Glucose uptake was approx doubled in basal state (0 insulin) in response to glyburide (2.8 + 0.4 vs 1.7 ± 0.2μ mol/g per hr).
  • 6.6. Maximal insulin (100 nM) stimulated glucose uptake tended to be higher in the glyburide treated group, but did not reach statistical significance (8.0 ± 0.7 vs 7.0 ± 0.6 μmol/g per hr).
  • 7.7. Western analysis revealed no significant effect of glyburide on the GLUT4 protein level in skeletal muscle.
  • 8.8. These results suggest that glyburide alters glucose uptake through some mechanism other than alterations in the level of the GLUT4 glucose transporter protein.
  相似文献   

6.
  • 1.1. In sea-water, adult salmon (S. salar) exchange an average of 12.6% of total body sodium/hr.
  • 2.2. Following transfer to fresh water sodium uptake follows Michaelis-Menton kinetics. Fmax = 2.40 mmol Na/1 ECF/hr, Km = 0.26 mmol Na/1. The uptake system is fully activated immediately following transfer to fresh water.
  • 3.3. Post smolts adapted to sea-water for 3 months take up sodium at only one third of the rate of adult fish following return to fresh water.
  • 4.4. The concentration of prolactin in the plasma is low in sea-water adapted fish and does not rise during the first 8 hr in fresh water.
  • 5.5. At pH 5 sodium uptake is reduced by almost 90%, even in the absence of aluminium, but recovers immediately on return to neutral water.
  • 6.6. At pH 5 and 20 μmol Al/1 there is little further effect on sodium uptake but after 6 hr in aluminium the inhibition of sodium uptake continues after return to neutral aluminium fresh water and uptake is only 50% of normal 24 hr later.
  相似文献   

7.
  • 1.1. The vitellogenic cycle of female tuatara was investigated by monitoring plasma levels of vitellogenin, calcium, total protein, inorganic phosphate (P1) and cholesterol.
  • 2.2. Vitellogenin was not detected in females in the non-reproductive condition, but was found perenially in plasma of reproducing females during vitellogenesis, which normally lasts about 3 years out of the 4 year ovarian cycle.
  • 3.3. No large year-to-year variations were found in the plasma constituents measured and there was no correlation between the oestradiol peak at mating and plasma levels of vitellogenin.
  • 4.4. The results provide further evidence that tuatara have an extraordinary prolonged and gradual vitellogenic cycle spanning several years for a single clutch of eggs. This type of reproductive cycle is unique among reptiles.
  相似文献   

8.
  • 1.1. Five adult, female alligators (Alligator mississippiensis) were captured at night during the breeding season, and a blood sample taken within 5 min of capture.
  • 2.2. The alligators were physically restrained (tied to boards) and additional blood samples taken at 4, 8, 12, 16, 22, 28, 38, and 48 hr after capture. After the last blood sample was collected the animals were released.
  • 3.3. Plasma estradiol-17β and corticosterone were measured by radioimmunoassay. Estradiol declined significantly from initial values by 22 hr post capture, but remained unchanged for 48 hr.
  • 4.4. Plasma corticosterone rose from a mean of 0.8 ng/ml at capture to 12.6 ng/ml after 4 hr. Corticosterone continued to rise up to 16 hr then declined after 22 hr. From 28 until 48 hr corticosterone again increased significantly.
  • 5.5. These results demonstrate that acute stress in female alligators causes significant suppression of plasma estradiol and a biphasic pattern of corticosterone secretion.
  相似文献   

9.
  • 1.1. Pupae of Galleria mellonella and Pieris brassicae given an injection with live, non-pathogenic Enterobacter cloacae or abiotic foreign molecules induce an acquired immunity that corresponds with the synthesis of haemolymph proteins of antibacterial activity.
  • 2.2. This humoral defensive response which persists for several days, differs quantitatively between insect species and between the inducers used, although very different foreign bodies induced the same immune proteins in both lepidopteran insects.
  • 3.3. A stronger and longer lasting response was consistently noticed in pupae immunized with non-pathogenic bacterium than after sterile nutrient broth injections.
  • 4.4. A demonstrably elevated activity of haemolymph lysozyme and trace activity of cecropins found in pupae of Galleria treated with saline W, a salt solution physiological to moths, disappear soon after 36 hr from injection.
  • 5.5. In P. brassicae, however, sterile insect Ringer can give a varying, if present at all, immune response.
  • 6.6. A mechanical injury (sterile wounding of insect body) can occasionally induce a similar but much weaker response.
  • 7.7. The antibacterial activity was drastically reduced in Pieris or completely depressed in most pupae of Galleria when actinomycin D or cycloheximide was given at an early time post-immunization with E. cloacae.
  • 8.8. It is concluded that the de novo synthesis of ribonucleic acid and immune proteins is required for expression of antibacterial activity in pupal haemolymphs.
  • 9.9. The synthesis of an immune mRNA was completed about 7 hr after the injection of the immunizing bacteria.
  相似文献   

10.
  • 1.1. To evaluate changes in high-energy phosphate metabolism in the water scorpion (Ranatra chinensis) under restraint and cold water-warm water stresses, in vivo [31P]NMR spectra were obtained.
  • 2.2. Under restraint stress, arginine phosphate (Arg-P) decreased by 10% after 1 hr and remained at that level thereafter, while β-ATP showed negligible changes over 6 hr.
  • 3.3. As the water temperature gradually increased or decreased, the relative concentration of Arg-P decreased due to enzyme regulation.
  • 4.4. Repeated cold water-warm water stress, which consisted of repeated 15 min exposures to cold water (5°C) followed by 15 min exposures to warm water (30°C) caused distinct decreases in Arg-P and β-ATP concentration. These decreases were dependent on the frequency of exposure.
  • 5.5. Phosphomonoesters (PME) increased not only with restraint stress but also with cold water-warm water stress.
  • 6.6. The effect of cold water-warm water stress on high-energy phosphate metabolism was greater than that of restraint stress.
  相似文献   

11.
  • 1.1. The locust vitellogenin (VTG) receptor which is embedded in oocyte plasma membranes is a glycoprotein.
  • 2.2. With various lectins oligosaccharide units have been identified, among them neuraminic acid linked to Gal or GalNAc, mannose chains, Gal linked to GalNAc or GlcNAc and fucose linked to GlcNAc.
  • 3.3. With specific enzymes it could be shown that mannose and most other oligosaccharides are O-linked while others like fucose are N-linked.
  • 4.4. Enzymatic removal of all O-linked carbohydrates resulted in a drop of the molecular mass of the receptor protein from 200,000 to 110,000.
  • 5.5. A total of N- and O-linked oligosaccharides of 54% was calculated.
  • 6.6. The isoelectric point of the receptor was found to be at pH 3.4 increasing slightly after removal of neuraminic acid.
  • 7.7. Removal of neuraminic acids destroyed the binding ability for VTG.
  相似文献   

12.
  • 1.1. A female specific protein (FSP, vitellogenin) in hemolymph and its related ovarian protein (vitellin) of Pandalus kessleri were studied by means of electrophoretical and immunological procedures.
  • 2.2. The vitellin was purified from vitellogenic ovaries using hydroxylapatite, DEAE cellulose and Sepharose 6B columns, consecutively.
  • 3.3. The vitellin had a molecular weight of approximately 560 kD and was composed of two subunits, 81 and 110 kD, respectively.
  • 4.4. The vitellogenin concentrations in the hemolymph increased as vitellogenesis in the ovarian oocytes advanced and dropped markedly after the release of mature eggs.
  相似文献   

13.
  • 1.1. Glucose entry rate was measured in two camels (Camelus dromedarius) and two sheep (Ovis wies) in the fed state and also after 72 hr of fasting.
  • 2.2. Plasma glucose concentration in the fed camels (129 mg/100 ml) was considerably higher than that of the fed sheep (63 mg/100 ml).
  • 3.3. The mean glucose entry rate in the fed camels (1.67mg/min per kg body wt) was very similar to the sheep (1.79 mg/min per kg body wt).
  • 4.4. When the results were expressed as a function of the metabolic body size, the entry rates in the camel were 1.5 times greater than that of the sheep.
  • 5.5. The relationship between glucose entry rate and plasma glucose concentration in different mammalian species is discussed.
  相似文献   

14.
  • 1.1. The ability to tolerate extracellular freezing as an adaptation for winter survival was tested in seven species of terrestrially-hibernating amphibians found in eastern Canada.
  • 2.2. All species had only moderate supercooling abilities, with whole animal supercooling points of −1.5 to −3°C.
  • 3.3. Two salamander species, Plethodon cinereus and Ambystoma laterale, and the toad, Bufo americamts, were freezing intolerant and were killed when frozen for 24 hr at temperatures just below their supercooling points. The major winter strategy of these animals appears to be behavioural avoidance of subzero temperatures.
  • 4.4. Four species of frogs Rana sylvatica, Hyla versicolor, Hyla crucifer and Pseudacris triseriata, survived extracellular freezing at moderate subzero temperatures (−2 to −4°C) for periods of time ranging up to 2 weeks.
  • 5.5. All four frog species accumulated low molecular weight carbohydrates as cryoprotectants, glycerol being the major cryoprotectant in adult H. versicolor, while immature adults of this species as well as the other three species all produced high levels of glucose as the cryoprotectant.
  相似文献   

15.
  • 1.1. The resistance of sub-tropical horses, and desert-dwelling horses to 72 hr dehydration/24 hr rehydration was investigated via changes in red cell parameters and plasma protein concentration.
  • 2.2. Red cell count, haemoglobin and haematocrit increased up to 48 hr dehydration. Between 48 and 72 hr dehydration these parameters decreased, implying a fluid shift onto the intravascular space from the interstitium/hindgut. Most parameters had regained baseline values by 24 hr rehydration.
  • 3.3. Mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration and total plasma protein were not significantly different between breeds at, or between most stages of hydration.
  • 4.4. Protection of plasma volume during dehydration/rehydration was aided by maintaining intravascular protein (especially albumin) levels. Red cells were transiently dehydrated and overhydrated but resisted osmolysis.
  相似文献   

16.
  • 1.1. Fat body from feeding-phase, last instar gypsy moth females incorporates l-[35S]methionine in vitro into two vitellogenins with the same molecular masses (165 and 180 kDa) as the apo-vitellogenins found in teh hemolymph and the apo-vitellins in teh eggs.
  • 2.2. Both apo-vitellogenins are observed in the medium of fat body cultures, but only the 180 kDa apo-vitellogenin is observed in extracts of cultured tissue.
  • 3.3. Synthesis and accumulation of the apo-vitellogenins are suppressed in a dose-dependent manner by topical treatment with the juvenile hormone analog, methoprene, prior to day 4.
  • 4.4. This suppression suggests that a declining juvenile hormone titre is involved in the initiation of vitellogenin synthesis.
  相似文献   

17.
  • 1.1. The capacity of five anuran Amphibians (Bufo viridis B. regularis, Rana ridibunda, Hyla arborea and Pelobates syriacus) to acclimate to NaCl and urea solutions was investigated.
  • 2.2. All species could be acclimated to relatively high concentrations of urea solutions, while only Bufo viridis and Hyla arborea could be acclimated to 500 mOsm/kg or higher NaCl solutions.
  • 3.3. The plasma urea concentration in B. viridis and H. arborea was elevated to levels over 140 mmol/1.
  • 4.4. The sum of plasma sodium and chloride concentrations did not increase over 400 mmol/l in any species.
  • 5.5. Urine osmolality, which was normally low, increased, but never exceeded the plasma osmolality.
  • 6.6. In the urea acclimation conditions, urine electrolytes diminished, similarly in all species in this study.
  • 7.7. It is concluded that anuran Amphibians can tolerate high plasma urea concentrations, but only those species which can elevate it, either through retention or net synthesis, can be acclimated to high salt solutions.
  相似文献   

18.
  • 1.1. Resting oxygen consumption at 10°C did not change from normoxia (150 mm Hg) down to an oxygen tension of 55 mm Hg for the flounder, Platichtys flesus.
  • 2.2. Flounders exposed to hypoxia showed increased levels of blood glucose and lactate, dependent on the degree of hypoxia.
  • 3.3. Due to hypoxia glycogen was depleted in the liver and swimming muscle but in the heart there was no significant change.
  • 4.4. Liver glucose increased after 7 hr of hypoxia. Heart and muscle glucose did not change but the absolute glucose concentration in the heart was five times higher than in the muscle.
  • 5.5. There is a transient accumulation of lactate in heart, liver and kidney after 7 hr of hypoxia while lactate accumulation in the swimming muscle is significant only after 21 hr of hypoxia.
  • 6.6. Succinate only accumulated in the liver while alanine accumulated in muscle, heart and liver.
  相似文献   

19.
  • 1.1. Blood volume and plasma biochemical changes and feed and water consumption in response to a hemorrhage by phlebotomy of 30% of the calculated total blood volume with and without replacement of blood volume with physiological saline were determined in juvenile male Coturnix coturnix japonica.
  • 2.2. Plasma protein and osmolality decreased rapidly posthemorrhage and did not recover by 72 hr posthemorrhage.
  • 3.3. Plasma glucose, Na+ and K+ increased within Ihr postphlebotomy. Plasma Na+ returned to nonphlebotomized levels within 6 hr postphlebotomy.
  • 4.4. Saline replacement of blood volume resulted in hypervolemia within 3–5 min postphlebotomy.
  • 5.5. Phlebotomized quail receiving no saline recovered blood volume to 0 hr (nonphlebotomized) levels within l hr postphlebotomy.
  相似文献   

20.
  • 1.1. Three different species of native vitellogenin, designated Vgα, Vgβ and Vgγ, were detected by gradient polyacrylamide gel electrophoresis (2–16%) in the plasma of untreated mature female quail and in the plasma of estrogen-induced female or male quail. The molecular weights of Vgγ, Vgβ and Vgα (in order of increasing size) were estimated to be 400,000 to 450,000 (by PAGE) or 466,000 (by analytical ultracentrifugation).
  • 2.2. DEAE-cellulose chromatography resolved vitellogenin-containing plasma into peak IV, fractions of which contained Vgα and Vgβ in equal quantities, and peak III, fractions of which contained Vgα, Vgβ and Vgγ in varying proportions.
  • 3.3. Peak IV fractions disssociated to give two bands (designated Vg1 and Vg2) on SDS-polyacrylamide gel electrophoresis. Pooled peak III fractions and plasma from untreated female or estrogen-induced female and male quail dissociated to give three bands (Vg1, Vg2 and Vg3). The mol. wt of Vg1, Vg2 and Vg3 were approx. 232,500, 212,000 and 194,000, respectively.
  • 4.4. Peak III and peak IV vitellogenin fractions were shown to have similar amino acid compositions except that the peak III vitellogenin fraction contained twice as much cystine as the peak IV vitellogenin fraction (2.2 vs 1.1 mol%). The peak IV vitellogenin fraction contained more serine than the peak III vitellogenin fraction (11.8 vs 10.9 mol%) and more phosphorus (0.584 vs 0.516 nmol/μg protein).
  • 5.5. Vgα or Vg1, in trace amounts, were detected in the plasma of untreated male quail.
  • 6.6. The amino acid contents, phosphorus contents, and mol. wt of quail vitellogenins were similar to published values for other egg-laying species.
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号