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. The carnitine-responsive mutant yeast, Candida pintolopesii ATCC 26014 and the wild type strain (ATCC 22987) were used to investigate the role of carnitine and the carnitine acetyltransferase system.
  • 2.2. [3H]l-Carnitine, supplied to the cells, was incorporated into acetylcamitine and [14C]pantothenate was incorporated into CoA and its derivatives.
  • 3.3. Both bioautography and quantitative assays indicated that the relative amounts of CoA and acetylCoA were very different in the mutant and wild type cells.
  • 4.4. The wild type yeast maintained an acetylCoA/CoA ratio of 0.33 ± 0.09 indicating that most of the CoA in the cell is in the free CoA form. Carnitine was not required to establish this ratio nor did its presence lower it further.
  • 5.5. In contrast, the mutant cells contained a high acetylCoA/CoA ratio (12.8 ± 3.0).
  • 6.6. In the mutant cells, carnitine lowered the ratio by decreasing the intracellular acetylCoA concentration and releasing free CoA.
  • 7.7. These data indicated that wild type yeast possess an effective mechanism that is not related to the CAT system for regulating the acetylCoA/CoA ratio.
  • 8.8. This mechanism appears to be lacking in the mutant. The CAT system decreased the acetylCoA/CoA ratio in the mutant cells but not to the value which is found in the wild type strain.
  • 9.9. In both stains of Candida pintolopesii, in the presence of carnitine, an acetylcamitine pool can be created whose concentration exceeds that of acetylCoA.
  • 10.10. The intracellular apparent equilibrium constant (Kapp) for carnitine acetyltransferase for wild type Candida pintolopesii ATCC 22987 was 0.73 ± 0.12, close to the established value of 0.6, indicating that the CAT system ran close to equilibrium.
  • 11.11. The Kapp for the CAT system of the carnitine-responsive mutant yeast was 7.7 ± 1.7 indicating that this reaction was not at equilibrium.
  相似文献   

2.
  • 1.1. This study deals with the hematological and blood chemistry of 13 adult marsh harriers (Circus aeruginosus).
  • 2.2. No significant differences were observed between male and female groups in any of the parameters.
  • 3.3. The value of white blood cells was 14,677/mm3 heterophils and lymphocytes, these being the most abundant cellular type (81.42 and 12%, respectively).
  • 4.4. Urea and uric acid are present in approximately similar proportions, though birds are said to be uricotelic.
  • 5.5. The cholesterol concentration values determined in our study, are higher than those reported in most other birds.
  相似文献   

3.
  • 1.1. Growth rates and body condition factors for native wild and captive-raised juvenile alligators (Alligator mississippiensis) that had been released to the wild were studied using tag-recapture methods for 274 alligators over a 4-year period. Alligators were grouped by sex, size class, source (farm-released vs native wild) and as to whether they had overwintered or not.
  • 2.2. In most groups, the farm-released alligators grew significantly better than wild alligators matched for sex and size; in the remaining groups the post-release alligators grew as well as their counterparts, though not better.
  • 3.3. Overwintering tended to slow growth rates in both groups, but farm-released alligators still demonstrated superior growth over native wild alligators even after overwintering.
  • 4.4. Males tended to grow faster than females, though this trend was not always significantly greater. In no matched group did females grow faster than males.
  • 5.5. Growth rates diminished with increasing size in native wild alligators (smaller alligators grew faster), but growth rates of farm-released alligators remained accelerated even at the larger size classes.
  • 6.6. Growth curves were constructed using known recapture data with three growth models (von Bertlanffy, Gompertz and logistic); the calculated maximum attainable length and growth parameters were significantly larger (P < 0.01) for farm-released alligators than wild using all three models.
  • 7.7. Body condition factors were not different in captive-raised post-released alligators than native wild alligators.
  相似文献   

4.
  • 1.1. Hematocrit, total protein and glucose values were determined in blood samples from 19 marsh harriers (Circus aeruginosus), 10 males and nine females.
  • 2.2. The different parameters were studied on the basis of the ranges described in other birds.
  • 3.3. There was a significant correlation between weight and blood glucose level.
  相似文献   

5.
  • 1.1. Eggs of wild cod, and of farmed cod fed (a) a diet supplemented with astaxanthin and (b) a diet supplemented with both astaxanthin and canthaxanthin, were analysed with respect to carotenoids.
  • 2.2. The total carotenoid contents in eggs were 0.7 ppm for wild cod and 0.5 ppm for farmed cod.
  • 3.3. Cod, having white flesh, deposit ketocarotenoids in the eggs, preferably astaxanthin.
  • 4.4. Canthaxanthin can replace astaxanthin in the eggs, but astaxanthin appears to be deposited preferentially when both carotenoids are present in the diet.
  • 5.5. The isomer distribution of (3S, 3′S):(3R, 3′S, meso):(3R, 3′R) astaxanthin in the eggs reflected the isomer composition of the diet.
  • 6.6. Echinenone, 4′-hydroxyechinenone, adonixanthin and zeaxanthin encountered in cod eggs may represent reductive metabolites of canthaxanthin and astaxanthin.
  相似文献   

6.
  • 1.1. Changes in body composition during starvation were compared between germ-free (GF) and conventionalized (CVL) chicks in experiment 1. At 8 days of age, the GF birds were divided into two groups, i.e. GF and CVL groups. The CVL birds were inoculated with faeces from conventionally reared birds. Until 14 days of age, both birds were fed a diet ad lib, and thereafter starved for 6 days.
  • 2.2. Nitrogen loss during starvation was significantly lower in CVL birds, though the reverse was true for water loss. Fasting heat production was comparable between two environments.
  • 3.3. Influence of the gut microflora on body weight and nitrogen losses during starvation was investigated in birds prefed diets high or low in dietary protein in experiment 2.
  • 4.4. No significant effect of the gut microflora was observed in body weight and nitrogen losses. Body weight was severely reduced in birds prefed the high protein diet and nitrogen loss was lower in birds prefed the low protein diet.
  相似文献   

7.
  • 1.1. From 2 to 21 weeks of age, 150 female broiler-breeder chicks received one of three dietary treatments. Fifty received an ad libitum supply of food (treatment AL). The remaining 100 were given weighed (restricted) rations once a day, 50 receiving the amount per bird recommended in the Ross 1 Parent Stock Management Manual (treatment R) and the other 50 receiving twice this recommended amount (treatment 2R). Water was provided ad libitum for all treatment groups.
  • 2.2. The daily allowance for R birds increased from 26 g per bird at 2 weeks of age to 94 g at 21 weeks. The intake of AL birds meanwhile increased from 65 g at 2 weeks to 240 g at 19 weeks, before decreasing to about 200 g at 21 weeks.
  • 3.3. Median heat productions (H) per bird in the R and 2R treatment groups were, respectively, 65 and 40% lower than in the AL when adjustment was made for the reduced food intake of AL birds in the calorimeter chambers. The effects of dietary treatment on fasting H were proportionally similar.
  • 4.4. Because the increasing divergence in body weights would have made a large contribution to differences in H per bird, the results were adjusted to the median weight of 2.03 kg and to unit weight (1.00kg). Adjusted fasting heat production was 18 and 11% less in 2R and R birds than in those fed ad libitum.
  • 5.5. If age was included as a variate in the logarithmic multiple regression, H was proportional to body weight (W, kg) raised to the power 0.73; if age was not included, H was proportional to W0.55.
  • 6.6. Rectal temperature was 0.7°C higher in AL birds at ambient temperatures of both 23 and 28°C. All treatment groups had a higher rectal temperature at 28°C than at 23°C, with the AL birds most affected.
  • 7.7. Foot surface temperature of R birds at an ambient temperature of 23°C was 8°C lower than that of the 2R and AL groups, indicating peripheral vasoconstriction.
  • 8.8. Polypnea (panting) and wing-extension occurred frequently in the AL birds, which also had a greater water intake. It was also observed that the restricted birds tended to aggregate, while the AL groups tended to space themselves evenly about the pen.
  • 9.9. It was concluded that broiler breeder fowl responded to restricted food intake by a reduction in heat production over and above that resulting directly from reduced metabolism of food and reduced body weight. The reduced metabolic rate per unit of weight conferred a thermoregulatory advantage at high ambient temperature.
  相似文献   

8.
  • 1.1. In vivo incorporation into body lipids and breast muscle proteins from l-[U-14C]leucine was studied in genetically lean or fat male chickens, fed or starved, 1 or 24 hr after intraperitoneal injection.
  • 2.2. Lipogensis and portein synthesis from labelled leucine were significantly higher in fat chickens than in lean birds, particularly in those in the fed state.
  • 3.3. Radioactivity in the free amino acid pool was greater in fat birds irrespective of the nutritional state.
  • 4.4. However, utilization of injected l-[U-14C]leucine for lipogenesis was no more than 2%.
  相似文献   

9.
  • 1.1. The phosphorylation of Escherichia coli proteins was analyzed comparatively before and after induction of the SOS response in a temperature-sensitive mutant strain.
  • 2.2. The presence of phosphorylated proteins was evidenced by gel electrophoresis and autoradiography after labelling with radioactive orthophosphate in vivo or radioactive adenosine triphosphate in vitro.
  • 3.3. Significant changes in the intensity of protein labelling were observed upon induction of the SOS functions: six proteins were found to be more phosphorylated while two others were less phosphorylated. Moreover, five additional proteins appeared to become phosphorylated exclusively during the SOS response. The molecular mass and isoelectric point of these various proteins were determined.
  • 4.4. For most proteins, the changes in the pattern of protein phosphorylation were concomitant with variations in the amount of protein synthesized.
  • 5.5. The changes in the pattern of phosphoproteins observed during the SOS response were not due to the temperature shift required experimentally for expressing the SOS phenotype.
  • 6.6. Phosphorylation was found to be catalyzed by protein kinases that modify amino acid residues at hydroxyl groups in protein substrates.
  • 7.7. Both in vivo and in vitro studies brought evidence that neither RecA nor LexA, the two key regulatory proteins of the SOS functions, were capable of undergoing phosphorylation.
  相似文献   

10.
  • 1.1. The histopathology of zebra mussel populations (Dreissena polymorpha) which were transplanted and exposed in baskets in the Dutch sector of the River Maas (5 locations) were compared with indigenous wild mussels at the same locations and at a clean reference site in the Ijsselmeer.
  • 2.2. All groups were sectioned histologically and examined to quantify cytological damage and pathology of a wide range of tissues, as well as to examine parasitology and to assess their reproductive state.
  • 3.3. Results show a significant reduction in general cytological quality and an increase in observed pathological conditions in the wild populations at the 3 downstream stations.
  • 4.4. The transplanted (active biomonitoring) groups of mussels clearly showed a similar trend in condition after only 42 days exposure at these sites.
  • 5.5. The influence of an industrial spillage of Cd in the Maas during the exposures is examined against this background of locally varying “health”.
  相似文献   

11.
  • 1.1. Fifteen values were determined in blood samples from six buzzards (Buteo buteo) and six eagle owls (Bubo bubo) over the 24 hr of the day.
  • 2.2. Glucose, urea, uric acid, triglyceride and calcium values showed diurnal rhythms in both species. Their respective patterns of diurnal variation were compared.
  • 3.3. Phosphorus, cholesterol and cholinesterase levels underwent circadian rhythms only in the buzzards. Albumin/globulin and amylase exhibited diurnal variations exclusively in the eagle owls.
  • 4.4. Glutamatic oxaloacetic transaminase, albumin, globulin, total protein and creatinine concentrations did not show diurnal rhythms in either of the species.
  • 5.5. Blood values of the different parameters were studied on the basis of the ranges described in birds.
  相似文献   

12.
  • 1.1. The medial (MGF), lateral (LGF) and motor (RMS-2) giant neurons were confirmed as neural components in the earthworm Amynthas hawayanus polysynaptic reflex circuit by simultaneous potential recording and dye injection.
  • 2.2. The reflex was initiated from the mechanoreceptors when evoked by mechanical stimulation but electrical stimulation also evoked an antidromic response in the motoneuron.
  • 3.3. The primary reflex response propagates decrementally along both giant axons but directly evoked action potentials conduct in an all-or-none fashion.
  • 4.4. The secondary reflex response continues to propagate after the primary response disappears.
  • 5.5. A rhythmically discharging neuron of uncertain function was also identified.
  相似文献   

13.
  • 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   

14.
  • 1.1. The effects of benzo[a]pyrene (BaP) on the metabolism of progesterone and pregnenolone, and the effects of steroids on BaP metabolism were examined in pyloric caeca microsomes of female Asterias rubens.
  • 2.2. The patterns of metabolism of progesterone and pregnenolone in microsomes were similar to those found in previous studies for homogenates and tissue incubations of pyloric caeca.
  • 3.3. BaP reduced the rate of hydroxylation of progesterone and pregnenolone, but had no effect on metabolite formation by non-cytochrome P-450-catalysed reactions.
  • 4.4. Microsomal BaP hydroxylase activity was reduced by the presence of progesterone, but pregnenolone and testosterone had no such effect.
  • 5.5. The reductions in steroid or BaP metabolism were progressive with increasing ratios of the concentration of the interfering compound to that of the assay substrate and were maximally 50% or less at ratios of × 100.
  • 6.6. It is concluded that isoenzymic forms of cytochrome P-450 are present, with preferences towards either steroid or BaP metabolism. The implications of the results for the in vivo situation are discussed.
  相似文献   

15.
  • 1.1. Quantitative measurements of calbindin mRNA, calbindin protein and calcium uptake have been made in sectioned intestinal villi to determine the location and cellular characteristics of their expression in immature, point of lay and laying chickens.
  • 2.2. Trace amounts of calbindin mRNA were detected by in situ hybridization in enterocytes located around the crypt-villus junction in jejunal tissue taken from immature and point of lay chickens. Large amounts of calbindin mRNA were detected in upper crypt and all villus enterocytes in tissue taken from laying chickens. Maximal levels of calbindin mRNA occurred in the basal third of the villus in laying chickens.
  • 3.3. No calbindin was detected immunocytochemically in tissue taken from immature and point of lay chickens. Large amounts of calbindin were expressed in tissue taken from laying chickens. Maximal expression of calbindin in this case occurred in villus tip enterocytes.
  • 4.4. Rapid uptake of calcium by tissue taken from laying chickens was twice that found in immature and point of lay birds. Calcium uptake in tissue taken from laying hens was also shown by quantitative autoradiography to take place maximally in villus tip enterocytes.
  • 5.5. Regulation ofcalbindin gene expression and the cellular characteristics of calcium transport in laying chickens are discussed in terms of an adaptive response taking place in birds undergoing a daily loss of egg shell calcium.
  相似文献   

16.
  • 1.1. Our knowledge of parasite born e diseases of cultured marine fish is restricted by the limited extent of practiced mariculture.
  • 2.2. Several parasites, pathogenic to fish including capsaloid, microcotylid and diclidophoran monogeneans and caligid copepods are ubiquitous in mariculture systems in diverse species of fish and geographical regions.
  • 3.3. The alga Amyloodinium ocellatum and the ciliated protozoan Cryptocaryon irritons are not as ubiquitous, but nevertheless present the most serious risk to farmed fish of most species due to their high pathogenicity, fecundity and resistance to conventional means of control.
  • 4.4. Infections in maricultured fish are dominated by monoxenous parasites. Occurence of heteroxenous parasites is restricted by their requirement for additional hosts to maintain transmission.
  • 5.5. Cage culture allows free exchange of infection between caged and native fishes; in inshore systems infections have to be introduced primarily from external sources.
  • 6.6. Water supply does not appear to be an efficient route of entry of infection into culture systems; parasites are introduced either by wild fry or wild breeders collected into the system, or with wild fish infiltrating via water supply or drainage.
  • 7.7. Adverse growth conditions are the most common circumstances in outbreak of epizooites. Over-crowding does not appear to promote primarily epizooites, its impact is indirect by contributing to the deterioration of the growth conditions.
  • 8.8. Epizooites are likely to occur also in juvenile, immunologically naive fish as well as following introduction of parasites into unexperienced fish population.
  • 9.9. Control has been implemented thus far through an empirical approach. Recent research is geared towards the development of methodology specifically designed to the needs of mariculture.
  相似文献   

17.
  • 1.1. The phenoloxidase activity, protein and carbohydrate levels were studied for 24 hr in the hemolymph of the migratory grasshopper, Melanoplus sanguinipes after artificial wounding of the insect cuticle or the injection of Beauveria bassiana conidia.
  • 2.2. Injection or wounding induced a primary response and phenoloxidase activity was found to increase within 10–60 min. The values for phenoloxidase activity in viable B. bassiana-injected insects exhibited a secondary response, i.e., an increase 24 hr after injection.
  • 3.3. In wounded insects and those injected with inactivated conidia, the phenoloxidase activity receded after the initial increase and remained at low levels.
  • 4.4. Protein concentrations in the hemolymph increased immediately after infection and wounding and returned to basal levels during the course of the experiment.
  • 5.5. Injection of viable B. bassiana resulted in a gradual increase in the protein concentrations between 12 and 24 hr.
  • 6.6. There was no apparent change in the carbohydrate levels in either B. bassiana-infected or wounded insects.
  • 7.7. These results are discussed in relation to their possible role(s) and interrelationships in the immune response to infection or wounding. Furthermore, we suggest that a “factor” is released after mechanical injury of the integument.
  相似文献   

18.
  • 1.1. The electric organ discharge (EOD) frequency modulations evoked by brief water vibration were analysed in the pulse-type fish Gymnotus carapo.
  • 2.2. The response consisted of a transient increase of the EOD frequency at short latency (30 msec). Response profiles were characteristic of the specimen and relatively independent on stimulus intensity.
  • 3.3. Conversely, they were dependent on stimulation sequence, showing a rapid decrement along successive stimuli and high temporal discrimination.
  • 4.4. The brief latencies indicate a relatively simple neural circuit.
  • 5.5. The response may be an electrolocation enhancement strategy for the detection of moving objects based on “sampling” the periphery at a higher frequency.
  相似文献   

19.
  • 1.1. 1H NMR spectra of the duodenum, jejunum and ileum tissues of the small intestine of a rat showed metabolic gradients.
  • 2.2. The concentrations of metabolites in these gut regions were altered by the presence of the tapeworm Hymenolepis diminuta.
  • 3.3. In the infected duodenum there was significantly less glycogen, glucose and phosphocreatine/creatine, but significantly more lactate than in the corresponding controls.
  • 4.4. Infected jejunum contained significantly less betaine but significantly more succinate, alanine and lactate.
  • 5.5. Infected ileum had significantly less glycogen and taurine but significantly more alanine and lactate.
  相似文献   

20.
  • 1.1. Goldfish (Carassius auratus) were fitted with ECG electrodes and intra-cranial stainless steel electrodes to monitor cardiac, EEG and SPS responses, during minimal restraint, to presentation of environmental stimuli (light-on, moving shadow, tap).
  • 2.2. All three stimuli evoked a bradycardia and increases in the EEG frequency; correlates of arousal responses in fish.
  • 3.3. EEG frequency changes were most evident in the fore- and midbrain regions; in the hindbrain smaller responses nevertheless showed discrimination between stimuli.
  • 4.4. EEG amplitude changes were more site- and stimulus-specific than frequency changes.
  • 5.5. SPSs occurred on stimulus presentations which were negative in polarity in the midbrain and positive in the forebrain and hindbrain, though the latter were smaller and less consistent.
  • 6.6. Principal components analyses and regression analyses were used to examine detailed associations between peripheral and central physiological changes.
  • 7.7. It was found that increases in the EEG frequency of fore- and midbrain regions were related to cardiac deceleration on early stimulus presentations.
  • 8.8. This was also shown for the negative SPS of the midbrain to the presentation of the tap stimulus.
  • 9.9. Positive SPSs of the forebrain were related to the bradycardia on later stimulus presentation i.e. during habituation of the arousal response.
  • 10.10. The results indicate that in fish, as in other vertebrates, negative SPSs in the midbrain are associated with arousal and implicate the forebrain in the modulation of arousal by its habituation.
  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