共查询到20条相似文献,搜索用时 31 毫秒
1.
Lea MA Bonadonna F Hindell MA Guinet C Goldsworthy SD 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2002,132(2):321-331
The estimation of milk consumption in free-ranging seals using tritium dilution techniques makes the key assumption that the animals drink no pre-formed water during the experimental period. However, frequent observations of unweaned Antarctic fur seal pups drinking water at Iles Kerguelen necessitated the testing of this assumption. We estimated water flux rates of 30 pups (10.7+/-0.3 kg) in four experimental groups by isotopic dilution over 4 days. The groups were: (1) pups held in an open air enclosure without access to water to estimate fasting metabolic water production (MWP); (2) free-ranging pups not administered additional water; (3) pups held in an open air enclosure and given a total of 300 ml of fresh water to verify technique accuracy; and (4) free-ranging pups given 200 ml of fresh water. Pups without access to water exhibited water flux rates (20.5+/-0.8 ml kg(-1)d(-1)), which were significantly lower than those observed for the free-ranging group (33.0+/-1.7 ml kg(-1) d(-1)). Mean estimated pre-formed water intake for the free-ranging experimental groups was 12.6 ml kg(-1) d(-1). Thus, MWP, measured as total water intake during fasting, may be significantly over-estimated in free-ranging Antarctic fur seal pups at Iles Kerguelen and at other sites and subsequently milk intake rates may be underestimated. 相似文献
2.
J. E. Mellish S. J. Iverson W. D. Bowen M. O. Hammill 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(6):377-390
Hooded seals (Cystophora cristata) lactate for 3.6 days during which females simultaneously fast and transfer large amounts of energy to their pups through
fat-rich milk. Pups grow rapidly, principally due to blubber deposition. Lipoprotein lipase (LPL), the primary enzyme responsible
for tissue uptake of triglyceride fatty acids, may strongly influence both maternal milk fat secretion and pup blubber deposition.
We measured the energetic costs of lactation (using hydrogen isotope dilution, 3H20), milk composition, prolactin, and LPL activity (post-heparin plasma LPL [PH LPL], blubber, mammary gland and milk; U) in
six females. PH LPL and blubber LPL were measured in their pups. Females depleted 216.3 MJ · day−1 of body energy and fat accounted for 59% of maternal mass loss and 90% of postpartum body energy loss, but maternal body
composition changed little. Maternal blubber LPL was negligible (0.0–0.2 U), while mammary LPL was elevated (1.8–2.5 U) and
was paralleled by changes in prolactin. Estimated total mammary LPL activity was high (up to 20,000 U · animal−1) effectively favoring the mammary gland for lipid uptake. Levels of total blubber LPL in pups increased seven-fold over lactation.
Pups with higher PH LPL at birth had greater relative growth rates (P = 0.025). Pups with greater blubber stores and total blubber LPL activity had elevated rates of fat deposition (P = 0.035).
Accepted: 4 May 1999 相似文献
3.
Galeriu D Crout NM Melintescu A Beresford NA Peterson SR Van Hees M 《Radiation and environmental biophysics》2001,40(4):325-334
Tritium is a potentially important environmental contaminant originating from the nuclear industry, and its behaviour in the
environment is controlled by that of hydrogen. Animal food products represent a potentially important source of tritium in
the human diet and a number of transfer coefficient values for tritium transfer to a limited number of animal products are
available. In this paper we present an approach for the derivation of tritium transfer coefficients which is based on the
metabolism of hydrogen in animals. The derived transfer coefficients separately account for transfer to and from free (i.e.
water) and organically bound tritium. A novel aspect of the approach is that tritium transfer can be predicted for any animal
product for which the required metabolic input parameters are available. The predicted transfer coefficients are compared
to available independent data. Agreement is good (R
2=0.97) with the exception of the transfer coefficient for transfer from tritiated water to organically bound tritium in ruminants.
This may be attributable to the particular characteristics of ruminant digestion. We show that tritium transfer coefficients
will vary in response to the metabolic status of an animal (e.g. stage of lactation, diet digestibility etc.) and that the
use of a single transfer coefficient from diet to animal product is inappropriate. It is possible to derive concentration
ratio values from the estimated transfer coefficients which relate the concentration of tritiated water and organically bound
tritium in an animal product to their respective concentrations in the animals diet. These concentration ratios are shown
to be less subject to metabolic variation and may be more useful radioecological parameters than transfer coefficients. For
tritiated water the concentration ratio shows little variation between animal products ranging from 0.59 to 0.82. In the case
of organically bound tritium the concentration ratios vary between animal products from 0.15 (goat milk) to 0.67 (eggs).
Received: 28 May 2001 / Accepted: 20 August 2001 相似文献
4.
Activity,milk intake and energy consumption in free-living ringed seal (Phoca hispida) pups 总被引:1,自引:1,他引:0
C. Lydersen M. O. Hammill 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1993,163(6):433-438
Measurements of growth, activity and energy consumption and estimates of milk intake were made in free-living, nursing ringed seal (Phoca hispida) pups. This was accomplished through the simultaneous use of time-depth recorders and the doubly labelled water technique. The pups spent an average of 52±7% of their time hauled out on the ice, 37±5% of the time in the water at the surface, and 11±5% of the time diving. Average daily mass gain of the pups (n=3) throughout the duration of the study period was 0.35±0.08 kg. The composition of the mass gain was 76% fat, 6% protein and 18% water. The total water flux was measured to be 52±10 ml·kg-1·day-1. Average CO2 production was 0.85±0.16 ml·g-1·h-1, corresponding to a field metabolic rate of 0.55±0.10 MJ·kg-1·day-1, or 3.8±0.6 times the predicted basal metabolic rate based on body size (Kleiber 1975). Average daily milk intake was estimated to be 1379±390 ml. The field metabolic rate for the different components of seal pup activity budgets were calculated to be FMRhaul out=1.34 BMR, FMRsurface=6.44 BMR, and FMRdiving=5.88 BMR.Abbreviations BMR
basal metabolic rate
- FMR
field metabolic rate
- HTO
tritiated water
- HT18O
doubly labelled water
- RQ
respiration quotient
- SDA
specific dynamic action
- TDR
time-depth recorder 相似文献
5.
S. J. Iverson O. T. Oftedal W. D. Bowen D. J. Boness J. Sampugna 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,165(1):1-12
Unlike most mammals, hooded seal (Cystophora cristata) pups are born with a substantial layer of adipose tissue. Subsequently, during the brief lactation period of only 4 days,
fasting mothers mobilize enormous amounts of lipid from blubber and secrete milk (60% fat) at rates of 10 kg·day-1. Pups gain 7 kg·day-1 due primarily to the deposition of fat in blubber. We measured blubber content and fatty acid composition of blubber and
milk in hooded seal mother-pup pairs at birth and over the 4-day lactation period to examine the nature and source of fetal
lipids, the incorporation of maternal blubber fatty acids into milk lipid, and patterns of fatty acid deposition in suckling
young. The fatty acid composition of the blubber of the newborn was notably different from that of its mother. Fetal deposition
was likely due to a combination of both fetal synthesis and direct placental transfer of maternal circulating fatty acids.
The blubber of the newborn was characterized by high levels (>90% of total fatty acids) of saturated and monounsaturated fatty
acids of primarily endogenous origin. In particular, the fetus appeared to have high Δ-9 desaturase activity as evidenced
by the large amounts of 14:1n-5 (4.2%) and 16:1n-7 (37.0%) in newborn blubber compared to maternal blubber (0.2% and 14.1%,
respectively). Nevertheless, essential and long-chain polyunsaturated fatty acids of the n-3 and n-6 families, which could
only have originated by direct transfer from the mother, comprised>7% of pup blubber fatty acids and indicated greater rates
of placental transfer than found in humans. In hooded seal mothers, rapid lipid transfer during the brief lactation period
appeared to be facilitated by direct incorporation of mobilized fatty acids into milk. Although some differences in proportions
of specific fatty acids were found between milk and maternal blubber, most of these differences declined over the course of
lactation. However, selective mobilization of 20:5n-3 from maternal blubber into milk was apparent throughout lactation and
resulted in elevated levels in pup blubber at weaning compared to maternal blubber. Ingested fatty acids were deposited directly
and without modification into the blubber of pups, and by 4 days the fatty acid composition of pup blubber was virtually identical
to that of the milk consumed. 相似文献
6.
C. Lydersen M. O. Hammill K. M. Kovacs 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,164(8):585-592
In this study we document growth, milk intake and energy consumption in nursing pups of icebreeding grey seals (Halichoerus grypus). Change in body composition of the pups, change in milk composition as lactation progresses, and mass transfer efficiency between nursing mothers and pups are also measured. Mass transfer efficiency between mother-pup pairs (n=8) was 42.5±8.4%. Pups were gaining a daily average of 2.0±0.7 kg (n=12), of which 75% was fat, 3% protein and 22% water. The total water influx was measured to be 43.23±8.07 ml·kg-1·day-1. Average CO2 production was 0.85±0.20 ml·g-1·h-1, which corresponds to a field metabolic rate of 0.55±0.13 MJ·kg-1·day-1, or 4.5±0.9 times the predicted basal metabolic rate based on body size (Kleiber 1975). Water and fat content in the milk changed dramatically as lacation progressed. At day 2 of nursing, fat and water content were 39.5±1.9% and 47.3±1.5%, respectively, while the corresponding figures for day 15 were 59.6±3.6% fat and 28.4±2.6% water. Protein content of the milk remained relatively stable during the lactation period with a value of 11.0±0.8% at day 2 and 10.4±0.3% at day 15. Pups drank an average of 3.5±0.9 kg of milk daily, corresponding to a milk intake of 1.75 kg per kg body mass gained. The average daily energy intake of pups was 82.58±19.80 MJ, while the energy built up daily in the tissue averaged 61.72±22.22 MJ. Thus, pups assimilated 74.7% of the energy they received via milk into body tissue. The lactation energetics of ice-breeding grey seals is very similar to that of their land-breeding counterparts.Abbreviations bm
body mass
- BMR
basal metabolic rate
- FMR
field metabolic rate
- IU
international unit
- RQ
respiration quotient
- HTO
tritiated water
- HT18O
doubly labeled water
- TBW
total body water
- VHF
very high frequency 相似文献
7.
Water flux and mass gain during lactation in free-living ringed seal (Phoca hispida) pups 总被引:1,自引:0,他引:1
Three ringed seal ( Phoca hispida ) pups were used to calculate water flux and milk intake, based on mass increase and dilution of injected tritiated water. Biological half life of tritium in ringed seal pups was 130 ± 17 h (mean ± S.D.). The plateau level of the isotope indicating equilibrium with the body water was, in all cases (N = 8), reached before the first blood sample was collected after 0·5 h. Daily water flux in the pups was 62·9 ± 21·5 ml kg-1 . Estimated daily milk intake of 1103 ± 388 ml milk resulted in a mass increase of 386 ± 104 g. Neonates had a fat content of 4·75%, and a water content of 70·1% (N = 3). Corresponding figures for a pup close to weaning were 36·5% and 46·3%. Isotope dilution calculations of body water gave an overestimate of 1·6% compared with body water content from desiccation. Ringed seal milk was found to contain 38·1% fat, 9·9% protein, 2·3% lactose and 1% ash. 相似文献
8.
C. Lydersen K. M. Kovacs M. O. Hammill I. Gjertz 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,166(7):405-411
In this study we measure energy intake via milk in nursing bearded seal (Erignathus barbatus) pups and determine how this energy is allocated into metabolism and storage of new tissues. This was accomplished using
longitudinal mass gain records and the doubly labelled water technique on nursing pups in combination with cross-sectional
data on changes in milk composition from bearded seal mothers. The pups (n=3) were all less than a week old at the start of the experiments. Pups gained 3.3±0.4 kg·day-1 of which 50% was fat, 14% protein and 36% water. Average daily water influx for the pups was 69.5±9.0 ml · kg-1· day-1. Average CO2 production during the study period was 0.99±0.10 ml·g-1·h-1, which corresponds to a field metabolic rate of 642±67 kJ·kg-1· day-1, or 6.0±0.5 times the predicted basal metabolic rate according to Kleiber (1975). The pups drank an average of 7.6±0.5 kg
of milk daily. This corresponds to a daily energy intake of 154±8 MJ, 47±14% of which was stored as new body tissue. Despite
this high energy intake bearded seal pups do not get as fat as do other nursing phocids. This is in part due to their larger
body size but also due to their very active aquatic lifestyle and the lower and more consistent fat content of the milk compared
to other phocid species. Bearded seal mothers forage during lactation and may also be involved in teaching their pups to feed
independently. All these data suggest that the lactation strategy of bearded seals differs from the phocid norm. 相似文献
9.
1. Isotopic signatures (δ15N and δ13C) from young‐of‐the‐year (YOY) yellow perch (Perca flavescens) were collected over the initial 4 month summer growing period from three separate and distinctive sites in northern Alberta, Canada. Data were analysed to test the hypotheses that there are within‐ and among‐population differences in the patterns of isotopic δ15N and δ13C change over the growing season, and that observed isotopic dilution and/or enrichment patterns were influenced by site‐specific physical and chemical factors. 2. Increases in δ15N relative to spawned egg masses were observed in immediate posthatch (emergent) YOY and attributed to enrichment associated with the assimilation of yolk during embryonic development. 3. Posthatch dilution of YOY δ15N signatures associated with ontogenetic dietary shifts from yolk to exogenous feeding and zooplanktivory to benthivory occurred at all sites and was associated at most sites with a concomitant increase in δ13C. 4. The rate and pattern of δ15N dilution and δ13C enrichment observed for the study populations varied between and within sites and depended on maternal trophic status and timing of ontogenetic dietary shifts, as determined by prey availability and site‐specific biogeochemical factors. 5. Comparisons of isotopic dilution patterns among species, using results from this study and literature‐derived values, indicated that dilution rates and patterns are species dependent and may vary in relation to key life‐history events. 6. Seasonal and spatial isotopic variability among populations and between species complicates field sampling. In particular, the connectivity to site‐specific conditions found here suggests that for locally resident juvenile fishes, spatial, as well as temporal variability must be included in isotopic sampling programmes designed to characterise littoral zone foodweb relationships. 相似文献
10.
J. P. Y. Arnould J. A. Green D. R. Rawlins 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2001,129(4)
The metabolism of 52–73-day old Antarctic fur seal pups from Bird Island, South Georgia, was investigated during fasting periods of normal duration while their mothers were at sea foraging. Body mass decreased exponentially with pups losing 3.5–3.8% of body mass per day. Resting metabolic rate also decreased exponentially from 172–197 ml (O2)·min−1 at the beginning of the fast and scaled to Mb0.74 at 2.3 times the level predicted for adult terrestrial mammals of similar size. While there was no significant sex difference in RMR, female pups had significantly higher (F1,18=6.614, P<0.019) mass-specific RMR than male pups throughout the fasting period. Fasting FMR was also significantly (t15=2.37, P<0.035) greater in females (823 kJ·kg−1·d−1) than males (686 kJ·kg−1·d−1). Average protein turnover during the study period was 19.3 g·d−1 and contributed to 5.4% of total energy expenditure, indicating the adoption of a protein-sparing strategy with a reliance on primarily lipid catabolism for metabolic energy. This is supported by observed decreases in plasma BUN, U/C, glucose and triglyceride concentrations, and an increase in β-HBA concentration, indicating that Antarctic fur seals pups adopt this strategy within 2–3 days of fasting. Mean RQ also decreased from 0.77 to 0.72 within 3 days of fasting, further supporting a rapid commencement of protein-sparing. However, RQ gradually increased thereafter to 0.77, suggesting a resumption of protein catabolism which was not substantiated by changes in plasma metabolites. Female pups had higher TBL (%) than males for any given mass, which is consistent with previous findings in this and other fur seal species, and suggests sex differences in metabolic fuel use. The observed changes in plasma metabolites and protein turnover, however, do not support this. 相似文献
11.
《Archives of animal nutrition》2013,67(3):221-242
Energy intake and milk production were measured in 12 mink dams raising litters of 3, 6 and 9 kits one to four weeks post partum by means of balance experiments and measurements of milk intake of the kits by the water isotope dilution technique. The dams were fed ad libitum on a conventional wet mink diet (DM: 323 g/kg; CP: 173 g/kg; ME: 4.4 MJ/kg). Milk samples collected from dams with corresponding litter sizes and lactation weeks, and body composition of kits nursed by these dams, were analysed for content of DM, ash, N and fat. The ME and drinking water consumption were higher in dams nursing 9 kits than in dams nursing 3 kits. The N and water balances as well as the live weight of dams were not affected by litter size. Daily milk production was higher in dams nursing 9 kits than in dams nursing 3 kits. The DM, N and fat content of the milk increased during lactation, but were not affected by litter size. Individual kit live weight was higher in litters of 3 than in litters of 6 and 9 kits four weeks post partum. The DM and fat content of the kits were lowest in kits from litters of 9 kits, whereas these kits had the highest protein content. Daily ME for maintenance of kits and the efficiency of utilisation of ME in milk for body gain were estimated to 356 kJ/kg0.75, kp ≈0.53 and kf ≈0.71, respectively. In conclusion, daily milk production increased with increasing litter size, but not in proportion to the number of kits, indicating that milk production limits the growth rate of the young. In the fourth week of lactation, milk production was not different between dams nursing 6 or 9 kits, indicating a maximum capacity. 相似文献
12.
Sarah Habran Cathy Debier Daniel E. Crocker Dorian S. Houser Gilles Lepoint Jean-Marie Bouquegneau Krishna Das 《Marine Mammal Science》2010,26(4):880-895
Effects of physiological processes such as gestation, lactation and nutritional stress on stable isotope ratios remain poorly understood. To determine their impact, we investigated these processes in simultaneously fasting and lactating northern elephant seals (Mirounga angustirostris). Stable carbon and nitrogen isotope values were measured in blood and milk of 10 mother-pup pairs on days 5 and 22 of lactation. As long- and short-term integrators of diet, blood cells and serum may reflect foraging data or energy reserves from late gestation and lactation, respectively. Limited changes in isotopic signatures of maternal blood over the lactating period were highlighted. Nitrogen isotope fractionation associated with mother-to-offspring transfer of nutrients was generated between mother and offspring during gestation and lactation. This fractionation was tissue and time-specific, it varied between early and late lactation from +0.6‰ to +1.3‰ in blood cells and from +1.1‰ to nonsignificant value in serum. Therefore, if pups appear to be good proxies to investigate the female trophic ecology especially for C sources, much more caution is required in using δ15N values. Further studies are also needed to better define the relative impact of fasting and lactation on the enrichment or depletion of isotopes in different tissues. 相似文献
13.
Summary The effect of gamma irradiation on tritium release into water (HTO) from phage T2-DNA-(methyl-3H) was studied in diluted aqueous solution. The influence of O2 and of citrate and phosphate buffer was investigated. In oxygenated solutions an enhancement ratio of 3 was found. From the linear dose yield relationsG values were calculated. In the presence of N2O tritium release was doubled, whereas tritium release decreased with increasing citrate concentration. It has been concluded that the major precursor of this tritium release is the OH radical. This was substantiated by experiments using thymine-(methyl-3H) and dimethylsulfoxide. 相似文献
14.
Phytoplankton competition along a gradient of dilution rates 总被引:4,自引:0,他引:4
Ulrich Sommer 《Oecologia》1986,68(4):503-506
Natural phytoplankton from Lake Constance was used for chemostat competition experiments performed at a variety of dilution rates. In the first series at high Si:P ratios and under uniform phosphorus limitation for all species, Synedra acus outcompeted all other species at all dilution rates up to 1.6 d-1, only at the highest dilution rate (2.0 d-1) Achnanthes minutissima was successful. In the second series in the absence of any Si a green algal replacement series was found, with Mougeotia thylespora dominant at the lowest dilution rates, Scenedesmus acutus at the intermediate ones, and Chlorella minutissima at the highest ones. The outcome of interspecific competition was not in contradiction with the Monod kinetics of P-limited growth of the five species, but no satisfactorily precise prediction of competitive performance can be derived from the Monod kinetics because of insufficient precision in the estimate of k
s
. 相似文献
15.
Gheorghe Benga Bogdan E. Chapman Guy C. Cox Philip W. Kuchel 《Cell biology international》2010,34(7):703-708
As part of a programme of comparative measurements of P d (diffusional water permeability) the RBCs (red blood cells) from an aquatic monotreme, platypus (Ornithorhynchus anatinus), and an aquatic reptile, saltwater crocodile (Crocodylus porosus) were studied. The mean diameter of platypus RBCs was estimated by light microscopy and found to be ~6.3 μm. P d was measured by using an Mn2+‐doping 1H NMR (nuclear magnetic resonance) technique. The P d (cm/s) values were relatively low: ~2.1×10?3 at 25°C, 2.5×10?3 at 30°C, 3.4×10?3 at 37°C and 4.5 at 42°C for the platypus RBCs and ~2.8×10?3 at 25°C, 3.2×10?3 at 30°C, 4.5×10?3 at 37°C and 5.7×10?3 at 42°C for the crocodile RBCs. In parallel with the low water permeability, the E a,d (activation energy of water diffusion) was relatively high, ~35 kJ/mol. These results suggest that “conventional” WCPs (water channel proteins), or AQPs (aquaporins), are probably absent from the plasma membranes of RBCs from both the platypus and the saltwater crocodile. 相似文献
16.
At-sea metabolism (CO2 production) and water turnover of six breeding Grey-headed Albatrosses Diomedea chrysostoma were measured, using the doubly labelled water method, at Bird Island, South Georgia, Mean food consumption (estimated from a water influx rate of 1.01 1 d-1 and data on dietary composition) was 1200gd-1 or 50.4 W. At-sea metabolism (derived from a rate of CO2 production of 3.98 1 h-1) was 27.7 W, 2.5 times the estimated basal metabolic rate (BMR). On average the birds ingested nearly twice as much food energy as they expended to obtain it. The metabolic rate during flight (estimated from at-sea metabolism and activity budget data) was 36.3 W (range 34.7–39.0 W) or 3.2 (range 3.0–3.4) times the predicted BMR. This is the lowest cost of flight yet measured, but consistent with the highly developed adaptations for economic flight shown by albatrosses. These results are briefly compared with data for other polar vertebrates (penguins, fur seals) exploiting similar prey. 相似文献
17.
S. J. Iverson M. Hamosh W. D. Bowen 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,165(5):384-395
Lipoprotein lipase regulates the hydrolysis of circulating triglyceride and the uptake of fatty acids by most tissues, including the mammary gland and adipose tissue. Thus, lipoprotein lipase is critical for the uptake and secretion of the long-chain fatty acids in milk and for the assimilation of a high-fat milk diet by suckling young. In the lactating female, lipoprotein lipase appears to be regulated such that levels in adipose tissue are almost completely depressed while those in the mammary gland are high. Thus, circulating fatty acids are directed to the mammary gland for milk fat production. Phocid seals serve as excellent models in the study of lipoprotein lipase and fat transfer during lactation because mothers may fast completely while secreting large quantities of high fat milks and pups deposit large amounts of fat as blubber. We measured pup body composition and milk fat intake by isotope (deuterium oxide) dilution and plasma post-heparin lipoprotein lipase activity in six grey seal (Halichoerus grypus) mother-pup pairs at birth and again late in the 16-day laction period. Maternal post-heparin lipoprotein lipase activity increased by an average of four-fold by late lactation (P=0.027), which paralleled an increase in milk fat concentration (from 38 to 56%; P=0.043). Increasing lipoprotein lipase activity was correlated with increasing milk fat output (1.3–2.1 kg fat per day) over lactation (P=0.019). Maternal plasma triglyceride (during fasting) was inversely correlated to lipoprotein lipase activity (P=0.027) and may be associated with the direct incorporation of longchain fatty acids from blubber into milk. In pups, post-heparin lipoprotein lipase activity was already high at birth and increased as total body fat content (P=0.028) and the ratio of body fat: protein incrased (P=0.036) during lactation. Although pup plasma triglyceride increased with increasing daily milk fat intake (P=0.023), pups effectively cleared lipid from the circulation and deposited 70% of milk fat consumed throughout lactation. Lipoprotein lipase may play an important role in the mechanisms involved with the extraordinary rates of fat transfer in phocid seals.Abbreviations
FFA
free fatty acid
-
HL
hepatic lipase
-
LPL
lipoprotein lipase
-
PH-HL
post-heparin hepatic lipase
-
PH-LPL
post-heparin lipoprotein lipase
-
VLDL
very low density lipoprotein 相似文献
18.
Daniel de los Cobos‐Vasconcelos Nora Ruiz‐Ordaz Juvencio Galíndez‐Mayer Héctor Poggi‐Varaldo Cleotilde Juàrez‐Ramírez López‐Muñoz Aarón 《Engineering in Life Science》2012,12(1):39-48
The biodegradation of the sulfonated azo dyes, Acid Orange 7 (AO7) and Acid Red 88 (AR88), by a bacterial consortium isolated from water and soil samples obtained from sites receiving discharges from textile industries, was evaluated. For a better removal of azo dyes and their biodegradation byproducts, an aerobically operated two‐stage rectangular packed‐bed biofilm reactor (2S‐RPBR) was constructed. Because the consortium's metabolic activity is affected by oxygen, the effect of the interstitial air flow rate QGI on 2S‐RPBR's zonal values of the oxygen mass transfer coefficient kLa was estimated. In the operational conditions probed in the bioreactor, the kLa values varied from 3 to 60 h?1, which roughly correspond to volumetric oxygen transfer rates, dcL/dt, ranging from 20 to 375 mg O2 L?1h?1. Complete biodegradation of azo dyes was attained at loading rates BV,AZ up to 40 mg L?1d?1. At higher BV,AZ values (80 mg L?1 d?1), dye decolorization and biodegradation of the intermediaries 4‐amino‐naphthalenesulphonic acid (4‐ANS) and 1‐amino‐2‐naphthol (1‐A2N) was almost complete. However, a diminution in COD and TOC removal efficiencies was observed in correspondence to the 4‐aminobenzenesulfonic acid (4‐ABS) accumulation in the bioreactor. Although the oxygen transport rate improved the azo dye mineralization, the results suggest that the removal efficiency of azo dyes was affected by biofilm detachment at relatively high QGI and BV,AZ values. After 225 days of continuous operation of the 2S‐RFBR, eight bacterial strains were isolated from the biofilm attached to the porous support. The identified genera were: Arthrobacter, Variovorax, Agrococcus, Sphingomonas, Sphingopyxis, Methylobacterium, Mesorhizobium, and Microbacterium. 相似文献
19.
Spatial variations in xylem sap flux density in evergreen oak trees with radial-porous wood: comparisons with anatomical observations 总被引:1,自引:0,他引:1
Makiko Tateishi Tomo’omi Kumagai Yasuhiro Utsumi Toshihiro Umebayashi Yasuki Shiiba Kazunobu Inoue Kiyohiro Kaji Keiichiro Cho Kyoichi Otsuki 《Trees - Structure and Function》2008,22(1):23-30
To estimate whole-tree water use when employing sap flow measurements, integration of the sap flux density (F
d) over the sapwood area is needed. Accordingly, it is necessary to obtain information on the characteristics of stem water
transportation such as spatial variations in F
d and the active xylem area in the stem cross-section. Although evergreen oak trees with radial-porous wood represent a major
component of secondary forests in western Japan, detailed information on their stem water transportation characteristics remains
unclear. In the present study, we used the heat dissipation method (Granier method) to conduct measurements of azimuthal and
radial variations in the F
d of Quercus glauca Thunb. ex Murray, a representative evergreen broad-leaved tree in western Japan. Further, by analyzing the anatomy of the
xylem structure, we examined why F
d varies spatially in the stem cross-section. By using a dye solution injected into a radial hole bored into the tree trunk,
we confirmed that the entire stem is hydroactive. We also compared the spatial variations in F
d and water conductivity per xylem area (K
s) which were estimated by using the observed vessel diameters and their density over the stem cross-section and Hagen–Poiseuille’s
law. Azimuthal and radial variations in F
d reached about 60 and 50% of the maximum values, respectively, and could be explained by spatial variation in K
s. As a result, we obtained statistical parameters describing the spatial variation in F
d in Q. glauca and determined that whole-tree water use estimated from measurements in one direction had at most ±20% potential errors for
studied trees. 相似文献
20.
Elena V. Navolotskaya Yulia A. Kovalitskaya Yury A. Zolotarev Vladimir B. Sadovnikov 《Journal of peptide science》2008,14(10):1121-1128
Selective agonist of nonopioid β‐endorphin receptor decapeptide immunorphin (SLTCLVKGFY) was labeled with tritium (the specific activity of 24 Ci/mmol). [3H]Immunorphin was found to bind to nonopioid β‐endorphin receptor of mouse peritoneal macrophages (Kd = 2.0 ± 0.1 nM ). The [3H]immunorphin specific binding with macrophages was inhibited by unlabeled β‐endorphin (Ki = 2.9 ± 0.2 nM ) and was not inhibited by unlabeled naloxone, α‐endorphin, γ‐endorphin and [Met5]enkephalin (Ki > 10 µM ). Thirty fragments of β‐endorphin have been synthesized and their ability to inhibit the [3H]immunorphin specific binding to macrophages was studied. Unlabeled fragment 12–19 (TPLVTLFK, the author's name of the peptide octarphin) was found to be the shortest peptide possessing practically the same inhibitory activity as β‐endorphin (Ki = 3.1 ± 0.3 nM ). The peptide octarphin was labeled with tritium (the specific activity of 28 Ci/mmol). [3H]Octarphin was found to bind to macrophages with high affinity (Kd = 2.3 ± 0.2 nM ). The specific binding of [3H]octarphin was inhibited by unlabeled immunorphin and β‐endorphin (Ki = 2.4 ± 0.2 and 2.7 ± 0.2 nM , respectively). Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd. 相似文献