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1.
The Norway Lobster Nephrops norvegicus (L.) was captured by trawling at depths of 120 to 150 m off the West Coast of Scotland using commercial fishing gears. Discarded animals (normally <25–35 mm carapace length) were sampled immediately after capture, and following emersion (exposure to air) on deck for 1 or 2 h. Their recovery from, and survival of, the stresses of being fished were examined in separate groups of animals transferred by SCUBA divers to underwater (u/w) cages on the seabed at a mean depth of 24 m. “Escaped” N. norvegicus were collected in a small-meshed (40 mm) “cover” around the cod-end and sampled without emersion. It was assumed that the physiological state of these animals would be similar to those passing through the cod-end meshes directly back into the surrounding sea during normal fishing operations. Groups of escaped animals were also transferred to u/w cages for recovery and survival studies. Control animals (creel-caught from the same fishing grounds) were sampled after recovery in u/w cages. Total body water content, haemolymph (blood) volume and composition were examined at various stages after capture and during recovery of control, discarded and escaped animals. Discarded animals showed significant reductions in total body water content compared to controls but recovered after 24 h. Controls that had been artificially damaged by puncturing also showed a reduction in water content. Escaped animals showed significantly higher mean water content compared to discards. Haemolymph volumes were also reduced in discarded animals suggesting that significant blood loss occurs during capture. There was also evidence of a shift of fluid from haemolymph to tissues in discarded animals. Pericardial (haemolymph) pressures were much reduced in discards compared to undisturbed control animals but showed significant recovery in surviving animals. Pressure reduction was less in escapes but was seen in control animals that had been exercised to exhaustion. Haemolymph osmotic concentrations, [Na +] and [K +] showed increases after discarding, notably after emersion, but haemocyanin [Hcy] and total haemolymph protein concentrations were less affected. The effect of these changes on longer term survival and recovery from the stress of capture are discussed. 相似文献
2.
A study of mixed apatites of the type Ca 10(PO 4) 6-x(OH) 2 has been undertaken in order to obtain an insight into the structural consequences of the incorporation of vanadium in the inorganic phase of bone. The crystallographic analysis as well as the vibrational spectra of these “models,” show that low or moderate VO 43− concentration does not produce any lattice distortion and has little effect on the strength of the P-O and O-H bonds. This study has also shown that the incorporation of VO 43− ions in the Ca 10(PO 4) 6(OH) 2 matrix at low temperatures is only possible if the hydroxyapatite is in the amorphous state. 相似文献
3.
Immune defence in creel-caught and trawled Nephrops norvegicus was investigated to assess a possible relationship between phenoloxidase (PO) activation and the total haemocyte count (THC). Capture, capture method and emersion evoked physiological and immunological responses that may have implications for the ability of N. norvegicus to survive the effects of such stressors. Haemolymph THC was always negatively related to PO activity in the trawled samples, suggesting a decreased level of the plasma serine proteinase inhibitors which reportedly regulate the ProPO system (Le Moullac et al. 1998; Fish shellfish Immunol 8:621-629). In contrast, creel-caught samples showed increased levels of both PO and THC (cf. control N. norvegicus), after a 12 h emersion period. Trawling and emersion evoked progressive and significant increases (p < 0.05) in the mean levels of haemolymph L-lactate, glucose and total ammonia. The evidence of overt activity and measured haemolymph parameters suggest that creel fishing yields N. norvegicus that are more likely to survive post-harvest treatments than those that are trawled. 相似文献
4.
Crustacean discards experience stress during commercial fishing operations, due to increased exercise while in the trawl and aerial exposure during sorting of the catch. Physiological stress and recovery were assessed following trawling of two ecologically important decapod species, regularly discarded in the Clyde Nephrops fishery. Haemolymph samples taken from trawled swimming crabs, Liocarcinus depurator, and squat lobsters, Munida rugosa, had significantly higher concentrations of ammonia (0.308 and 0.519 mmol l(-1)), D-glucose (0.14 and 0.097 mmol l(-1)) and L-lactate (6.2 and 0.87 mmol l(-1)) compared with controls, indicating an impairment of ammonia excretion and a switch to anaerobic metabolism. Concurrently, the haemolymph pH of trawled squat lobsters was low (7.47) compared with controls (7.75); however, the reverse trend was found in L. depurator. Initially elevated lactate (7.98 mmol l(-1)) and glucose (0.73 mmol l(-1)) concentrations of trawled and emersed (1 h) L. depurator were restored, 4 h after re-immersion along with pH (7.54). Crabs that had been emersed for 1 h had significantly higher concentrations of glucose (0.2 mmol l(-1)) and lactate (5.14 mmol l(-1)), and had more acidic blood (7.64) than L. depurator subject to 1 h of exercise, indicating that anoxia was the main cause of physiological stress. Crabs and squat lobsters lost 7% and 9% of their initial body wet weight following 1 h of emersion, although blood osmolarities did not change significantly. While all animals survived aerial exposure in our experiments, sorting of the catch on commercial boats takes up to 300 min, which could lead to mortality or sub-lethal chronic biochemical changes that could compromise fitness. 相似文献
5.
The use of specific and non-specific antisera for estradiol-17β (E 217β) were compared in the radioimmunoassay of the steroid. The effects of various “blank” mateirials on the standard curve and on the accuracy of recovery of E 217β added to plasma before and after chromatography on LH-20 Sephadex were examined. It was concluded that the use of the specific antiserum (anti-6-oxoE 217β -6-(O-carboxymethyl)oxime-bovine serum albumin(antiE 217β-6-BSA) was an improvement on the non-specific serum anti-E 217β-17-hemisuccinyl-bovine serum albumin (antiE 2 17β-17-BSA) following chromatography of extracts. However, although a precise result could be obtained with the anti-E 217β-6-BSA without the Chromatographic step,
recovery of E 217β added to plasma was only possible if the step was included. The cross-reactivity of estrone (E1)with E217β using anti-E217β-17-BSA as defined by Abraham (J. Clin. Endocr.
, 866 (1969) was examined under conditions of constant and of changing E1:E217β ratio. 相似文献
6.
Recently, it has been shown that PKA-mediated phosphorylation of the β 2-adrenergic receptor (β 2-AR) by the cyclic AMP-dependent protein kinase (PKA) reduces its affinity for G s and increases its affinity for G i. Here we demonstrate that, like the β 2-AR, the β 1-AR is also capable of “switching” its coupling from G s to G i in a PKA-dependent manner. The β 1-AR is capable of activating adenylate cyclase via G s, and can also activate the extracellular-regulated kinases, p44 and p42 (ERK1/2). In transfected CHO cells, the observed β 1-AR-mediated activation of ERK is both sensitive to pertussis toxin (PTX), indicating involvement of G i/G o, and to the PKA inhibitor, H-89. β 1-ARs with PKA phosphorylation sites mutated to alanines are unable to activate ERK. Mutating these same residues to aspartic acid, mimicking PKA phosphorylation, leads to a decrease in G s-stimulated cAMP accumulation and an increase in PTX-sensitive ERK activation. These results strongly support the hypothesis that the β 1-AR, like the β 2-AR, can undergo PKA-dependent “G s/G i switching”. 相似文献
7.
Cyclograpsus lavauxi H. Milne Edwards, 1853 occurs under boulders near the littoral fringe, where it is wetted only briefly, if at all, in each tide. Mean water content of sea-water equilibrated crabs was 62.3 % of body weight. On warm, windy days crabs on the shore lose > 17.5% of body water. Water loss for crabs of 1.6 g mean body weight was 0.29 % water content · h −1 · mm Hg saturation deficit −1, which is similar to that of species occupying positions lower on the shore. C. lavauxi is, however, able to tolerate comparatively greater losses of body water (up to 36%) compared with species from lower shore levels. As the gills dry, the lamellae separate into regular clumps which may help to maintain gas exchange. Resting oxygen consumption (Vo2) after 3–5 h settlement was similar in water and air. During enforced activity, Vo2 increased by factors of 5.3 in water and 2.6 in air at a standardized body weight of 1.5 g, indicating an appreciable aerobic scope in both media. Loss of up to 16% of body water did not depress resting aerial Vo2 or aerobic scope. In resting crabs there was no change in haemolymph pH after 24 h of either immersion or emersion, but haemolymph [Ca2+], [HCO−3] + [CO2−3], and calculated Pco2 all rose in air relative to aquatic values. These results suggest that cuticular or other endogenous CaCO3 is mobilized to compensate the respiratory acidosis in air. The implications of such physiological properties for aquatic and aerial activity on the shore are discussed. 相似文献
8.
The onset of and recovery from physiological stress in Liocarcinus depurator (Decapoda: Portunidae), that were trawled and subjected to emersion during fishing activities, was analysed in a field study
in the Northern Adriatic Sea. Our working hypothesis intended to assess the development of physiological impairment due to
air exposure during sorting operations, and the possible recovery trajectories after the return to sea of this by-caught species.
The protocol we used included experimental trawling and quantification of physiological stress indicators (haemolymph concentrations
of l-lactate, d-glucose, ammonia and pH) under different seasonal conditions. Immediately after being caught, when the fishing net was emptied
on board, L. depurator showed higher physiological imbalance in the summer vs. winter experiments, highlighting the immediate effect of temperature
shock due to the difference in temperature between the sea bottom and the deck (15–18 and 2°C in summer and winter, respectively).
Experimental animals in the permanently emersed condition exhibited a progressive disruption of homeostasis in both seasons,
as confirmed by a significant increase in lactate and a decrease in the pH of the haemolymph as a function of the emersion
time. Ammonia levels were almost stable in the summer, when the physiological limits of this metabolite were reached immediately
after animals were caught. In the winter, a significant increase in ammonia was observed over the time. This pattern can be
attributed to the impairment of gill function, resulting in suffocation (manifested by marked haemolymph acidosis) and reduced
ammonia excretion. Glucose concentration was revealed to be stable during air exposure in both seasons, though a higher concentration
was recorded in the summer compared to the winter. The recovered individuals tended to return to pre-caught values for all
of the haemolymph parameters we measured, though with different trajectories in the two seasons. From these results, we conclude
that temperature shock, coupled with air exposure, influenced the ultimate stress level of this species to a greater extent
than other effects of fishing. 相似文献
9.
The condition of trawled and creeled Norway lobsters, Nephrops norvegicus, was compared in individuals caught along the Swedish west coast. Female and male N. norvegicus were collected from trawled and creeled areas in the spring and autumn. Their nutritional state was determined by analysing individuals for haemocyanin concentration, the dry weight/wet weight relationship in muscle and hepatopancreas and the percentage dry weight of muscle and hepatopancreas of total animal dry weight. All parameters were measured on an individual basis and checked for size dependence. Creeled individuals were generally found to be in better condition than individuals from trawled areas, and animal condition increased from spring to autumn. Autumn males from creeled sites were overall in the best condition, having the highest mean haemocyanin concentration, muscle and hepatopancreas dry weight/wet weight relationship and percentage dry weight of muscle tissue. Claw symmetry (paired cutters) was suggested as an indicator of limb loss, with the highest occurrence found in females from trawled sites. Crusher absence had no effect on the animal's individual percentage dry weight of muscle, although the mean was lower in trawled females than in other groups. Resource limitation and physical stress are discussed as possible underlying factors affecting the observed differences. 相似文献
10.
For economic and logistical reasons, an increased proportion of landings from trawl caught Nephrops norvegicus is being used in the live export trade. This paper reports a series of trials that investigate the impact of capture method and trawl duration on the levels of stress, damage and mortality of N. norvegicus. The stress of N. norvegicus captured during trials in spring and autumn by means of short trawl (1 h duration), long trawl (5 h duration) and creeling was assessed using a range of physiological measures (for haemolymph l-lactate, crustacean hyperglycaemic hormone (CHH) and abdominal muscle glycogen concentrations), the immunological status (total haemocyte counts (THC)) and physical assessments (mortality, damage indices). N. norvegicus caught by creeling were generally less stressed (i.e. significantly lower haemolymph l-lactate and CHH concentrations) than their trawled counterparts. Increased duration of trawl did not significantly alter physiological parameters, while time of landing did have a significant effect on l-lactate concentrations, as individuals landed in the morning exhibited higher concentrations. Irrespective of the season in which trawling occurred, individuals captured by short trawls in the morning suffered lowest mortalities. Damage assessment data revealed that a greater proportion of individuals was categorised as heavily damaged following longer trawls conducted in spring. 相似文献
11.
The temperature dependence of S-state transitions in Photosystem II was measured by means of thermoluminescence using two different protocols for low-temperature flash excitation: protocol A, “last flash at low temperature”, and protocol B, “all flashes at low temperature”. Comparison of the temperature-dependence curves obtained by these two protocols revealed a marked difference particular for the three-flash experiments. The difference was attributed to the formation of a low-temperature sensitive precursor state between S 2 and S 3. The state is formed by two flash illumination given at −5 to −50°C, spontaneously transforms to normal S 3 on dark warming, and is not converted to S 0 by the 3rd flash. The precursor state was tentatively assigned to an S 3 in which H + release is not completed. 相似文献
12.
The rate of in vitro Nicotiana tabacum L. “Bel-W3” pollen tube growth was reduced 62 and 44%, respectively, when pollen tubes were exposed to 120 ppb ozone (O 3) for 3 hr or 300 μW/cm 2 ultraviolet-B (u.v.-B) radiation for 30 min. Petunia hybrida Vilm. “White Cascade” pollen tube growth was reduced 34 and 59%, respectively, upon exposure to O 3 or u.v.-B at the above doses. The combination of u.v.-B at 300 μW/cm 2 for 30 min, followed by O 3 at 120 ppb for 3 hr, reduced pollen tube growth by 79% for “Bel-W3” and 75% for “White Cascade”. The effect appeared to be additive, implying that different target areas may be affected by the two stressors. In the Northeast, plants are exposed to both u.v.-B and O 3 during the normal growing season. This may result in an unexpectedly higher stress on the reproductive system than had been previously suspected based on these two stressors acting individually. 相似文献
13.
Various sulfidic anions and the oxidizing cations [Ru(NH 3) 6] 3+ and N, N′-dimethyl-4,4′-bipyridinium 2+ (paraquat 2+) form ion pairs in aqueous solutions which display outer-sphere charge-transfer (CT) absorptions. The CT energies are used to establish a series of sulfidic anions with increasing CT donor strength: SCN −2O3 2−4 3−3S3−2 −2S2 −4 2−. 相似文献
14.
Fluorescence transients were measured in lyophilized maize chloroplasts (suspended in Tris-maleate buffer (pH 6.6)) after extraction with heptane. (The fluorescence characteristics before extraction were qualitatively similar to those in the fresh chloroplasts.) The initial fluorescence level ( m) in the (dry) heptane-extracted sample remained the same as in the unextracted material, but the variable fluorescence (Δ m) was drastically diminished. A portion of variable fluorescence, however, could be restored by adding Na 2S 2O 4. If the heptane extraction was made in the presence of water (wet), the m level was almost as high as (or higher than) the final level ( M) of the unextracted sample, and Δ m was reduced. The “jet” of O 2 (that measures the pool size of the intersystem intermediate A) and the “microjet” (that measures the pool size of the reaction center complex E), present in the unextracted samples, were absent in both types of extracted samples. Some of the above data may be interpreted in a hypothesis in which two quenchers (Q 1 and Q 2) control the fluorescence (O → P) of chloroplasts — the reduction of Q 1 being responsible for the rapid and that of Q 2 for the slow fluorescence rise. 相似文献
15.
The rates of respiratory O 2 uptake have been studied in leaves, stems and whole shoots of several freshwater plants: 6 angiosperms, 2 bryophytes and one alga. For angiosperm leaves, rates varied widely with species (30–142 μmol O 2 (gDW) −1 h −1), were correlated with chlorophyll content and were higher than those of the stems (13–71 μmol O 2 (gDQ) −1 h −1). The rates for the shoots of bryophytes (53–66 μmol O 2 (gDW) −1 h −1) and for the alga Cladophora glomerata (L.) Kütz. (96 μmol O 2 (gDW) −1 h −1) were slightly higher than those of most angiosperm stems, but lower than those for most leaves. These plants had a significant cyanide-resistant respiration, suggesting the existence of an alternative pathway to the “classic” cytochrome system. This pathway was found to be active in all the species studied, as judged by responses to a specific inhibitor, SHAM (salicylhydroxamic acid). Measurement of electron-transport system (ETS) activity showed that there is a large electron-transport capacity which is not normally used by respiration in vivo. 相似文献
16.
Ammonia is one of the most important contaminants impairing the quality of water resources. When this is considered along with the fact that the global demand for nitrogenous fertilizers is in constant rise, the need for recovery as well as removal of nitrogen is well justified. Crystallization of N and P in the form of struvite (MgNH 4PO 4·6H 2O), which is a slow releasing and valuable fertilizer, is one possible technique for this purpose. This study investigated the removal of NH 4+ through struvite precipitation from the effluents of one- (R1) and two-phase (R2) anaerobic reactors digesting dairy manure. To force the formation of struvite in the anaerobic reactor effluents, Mg 2+ ion was added by using both Mg(OH) 2 and MgCl 2·6H 2O. To prevent the effect of different total phosphorus (TP) concentration in the effluents of R1 and R2, as well as to not limit the formation of struvite, an excess amount of PO 43− (0.14 M) was added in the form of Na 2HPO 4. Different stoichiometric Mg 2+:NH 4+:PO 43− ratios were tested to determine the required Mg 2+ concentrations for maximum NH 4+ removal by keeping NH 4+:PO 43− ratio constant for the effluents of reactors R1 and R2. The results revealed that very high NH 4+ removal efficiencies (above 95%) were possible by adding Mg 2+ ions higher than 0.06 M concentration in the effluents from reactors R1 and R2. It was also observed that the initial pH adjustment to 8.50 using NaOH did not result in any significant increase in the removal of NH 4+ and the removal of NH 4+ in the reactors treated with MgCl 2·6H 2O was higher than those treated with Mg(OH) 2 for the same Mg 2+ concentration. 相似文献
17.
The effects of partition of substrates and product on the modelling of the microenvironment of an immobilized lipase were evaluated using Response Surface Methodology. The esterification of butyric acid with ethanol in n-hexane, catalyzed by Candida rugosa lipase immobilized in two biocompatible and relatively hydrophilic polyurethane foams (“Hypol FHP 2002™” and “Hypol FHP 5000™”) was used as the model system. For each set of initial conditions, the final concentration of substrates and ethyl butyrate in the microenvironment, at equilibrium, Cmicro, were estimated by mass balancing bulk and foams. The Cmicro values obtained were used to estimate the corresponding partition coefficients of ethanol (P EtOH), butyric acid (P BA) and ester (P EB), between the foams (microenvironment) and the bulk medium. Foams containing previously inactivated lipase, as well as lipase-free foams were used. For both substrates, Cmicro values were, in the majority of the experiments, higher than their macroenvironmental counterparts. The lowest Cmicro values were observed with the less hydrophilic foam (“FHP 5000”). A decrease of CmicroEtOH in both foams and CmicroBA in “FHP 5000” foams, was obtained upon lipase immobilization. P EB values were, in all cases, close to zero. This is beneficial in terms of the shift in reaction equilibrium, product recovery and alleviation of product inhibition effects. 相似文献
18.
Arterial pH, PCO 2 (P aCO 2), plasma bicarbonate [HCO 3− and respiratory frequency were measured in pigeons exposed to ambient temperatures ( TaS) of 30–60°C. Acclimated, nonpanting birds regulated acid-base balance at normal levels, when exposed to Tas) between 30 and 53°C Ta. At higher Tas (55–60°C), both nonpanting and panting acclimated pigeons regulated pH at normal levels, 7.544 ± 0.011 (SD) and 7.531 ± 0.022 (SD), respectively, accompanied by a slight hypocapnia, 24.8 ± 4.0 Torr and 23.8 ± 2.49 Torr (P aCO 2), respectively. Nonacclimated birds, exposed to 50°C Ta, endured a severe hypocapnia (P aCO 2 of 9.1 ± 2.52 Torr) and alkalosis (pH of 7.702 ± 0.048). Thirteen exposures to > 50°C T a, 4–6 h a day, resulted in a significant improvement in the capacity of the panting pigeon to maintain an almost normal acid-base balance, i.e. actual and standard [HCO 3− of 22.6 ± 1.22 and 25.7 ± 1.10 mM/l, respectively, and only a slight hypocapnia (P aCO 2 of 23.6 ± 3.9 Torr) and alkalosis (pH of 7.589). The suggestion that acclimation to high Tas (50–60°C) is needed for fine adjustment between the competing needs for heat dissipation, pulmonary gas exchange, and acid-base regulation in the heat-exposed pigeon is discussed. 相似文献
19.
Kinetics of the absorption change of P700 (blue band) and cytochrome f in whole cells of a blue-green alga, Plectonema boryanum, have been studied by Q-switched ruby-laser flash excitation (694 nm; approx. 20 nsec) to elucidate the sequential relationship of these two components in photosynthetic electron transport. “P700” was photooxidized within 2 μsec and recovered in two phases t1/2 10 μsec and 200 μsec). Under the same conditions cytochrome f was oxidized with a half time of 15 μsec. The magnitude of the fast phase of “P700” recovery, however, diminished at lower laser intensity while the cytochrome f change remained unaffected. The result suggests that cytochrome f and P700 may not be on the same electron-transport chain. 相似文献
20.
The “unprotected” Pt nanoclusters (average size 2 nm) mixed with the nanoscale SiO 2 particles (average size 13 nm) were used as a glucose oxidase immobilization carrier to fabricate the amperometric glucose biosensor. The bioactivity of glucose oxidase (GOx) immobilized on the composite was maintained and the as-prepared biosensor demonstrated high sensitivity (3.85 μA mM −1) and good stability in glucose solution. The Pt–SiO 2 biosensor showed a detection limit of 1.5 μM with a linear range from 0.27 to 4.08 mM. In addition, the biosensor can be operated under wide pH range (pH 4.9–7.5) without great changes in its sensitivity. Cyclic voltammetry measurements showed a mixed controlled electrode reaction. 相似文献
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