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51.
In this study, we aimed to clarify the mechanism of sinking death during the larval stage of Pacific Bluefin tuna Thunnus orientalis by investigating the effects of swimming performance on sinking death, using a behavioral approach. Swimming performance was examined 3–9 days after hatching (DAH) under day and night light conditions in cuboid experimental tanks. Swimming behavior variables such as swimming speed and swimming angle were measured under both light conditions. Larvae in the daytime experiment and larvae with inflated swim bladders at night were distributed on the surface layer of the water column. In contrast, larvae with uninflated swim bladders at night were frequently observed swimming vertically or sinking to the bottom of the tank. Larvae with inflated swim bladders at night were always distributed beneath the surface until the next morning (survival rates were 100 %). However, larvae with uninflated swim bladders at night swam upward repeatedly and later sank to the bottom of the tank (survival rates were 60 % and 38 % at 5 and 9 DAH, respectively). Larvae with uninflated swim bladders were not always able to maintain their swimming depth by swimming until the next morning. Additionally, their swimming speed and vertical swimming frequency (ratio) depended on the illumination and swim bladder conditions. Our findings show that larvae with uninflated swim bladders at night were associated with a higher risk of sinking death. The swimming energy capacity of Pacific Bluefin tuna larvae, which indicates the total amount of the energy that enables individuals to swim throughout the night without feeding, was found to be linked to sinking death. 相似文献
52.
ABSTRACT1. Reducing excessive chicken body fat deposition is a main goal of the poultry industry. Preadipocytes are important in adipose tissue growth and development.2. To discover proteins related to chicken fat deposition, two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) was used to identify differentially expressed proteins in preadipocytes derived from Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF).3. A total of 46 differentially expressed protein spots were found in the preadipocytes between fat and lean broilers. Matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) analysis showed the protein spots corresponded to 33 different proteins. The proteins were mainly related to biological oxidation, cell proliferation, cytoskeleton, lipid metabolism, molecular chaperone, protein synthesis and signal transduction.4. From the perspective of protein expression, these results lay a foundation for further study of the genetic mechanism of broiler adipose tissue growth and development. 相似文献
53.
Transgene expression was evaluated for Gladiolus plants transformed with either the CaMV 35S, double CaMV 35S, rolD, or Arabidopsis UBQ3 promoter controlling the uidA or bean yellow mosaic virus coat protein gene in either the sense or antisense orientation to determine differences in expression for plants grown in the greenhouse and outdoors for two years. There was more variability in GUS expression when plants were grown outdoors than in the greenhouse for two years. Four of the six transformed plant lines with the UBQ3, rolD, and CaMV 35S promoters grown outdoors showed significant differences in GUS expression from year to year as compared to two of the six lines with the UBQ3 and rolD promoters grown in the greenhouse. When grown the same year, two plant lines with the CaMV 35S and one line with the rolD promoter showed 2–16× higher levels of GUS expression outdoors than in the greenhouse, and one plant line with the UBQ3 promoter had 31× higher GUS expression in the greenhouse instead of outdoors. Three of six plant lines transformed with the bean yellow mosaic virus coat protein gene in either the sense or antisense orientation under control of the double CaMV 35S promoter showed obvious transgene expression as compared to three lines that did not show expression or negligible expression for both years when plants were grown both outdoors and in the greenhouse. This study verified long-term gene expression, rather than silencing, for Gladiolus plants when grown outdoors and in the greenhouse from year to year. 相似文献
54.
Seed production in orchards of Araucaria cunninghamii involves grafting plagiotropic scions (using a terminal-side graft) which exhibit a lateral growth habit onto decapitated stock trees. Decapitation effectively releases buds in the leaf axils of the stock plant from apical dominance and orthotropic replacement shoots develop rapidly. To prevent suppression of the grafted scion, frequent removal of orthotropic shoots is necessary. The trial application of several plant auxins at different concentrations to decapitated stock plants identified a suitable technique to simulate apical dominance and temporarily suppress the production of replacement shoots. The synthetic auxin IBA most effectively controlled the production and growth rate of replacement shoots with the least amount of damage to the treated tissues. Auxin application apparently enhanced the growth of lateral branches in the whorl immediately below the treated stem, suggesting that grafted scions would not be adversely affected by auxin treatment. Routine application of auxin to plagiotropic grafts will reduce maintenance costs in seed orchards and clone banks of A. cunninghamii. 相似文献
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Moritz Knoche Martin J. Bukovac Shoichi Nakagawa Garvin D. Crabtree 《Pest management science》1998,54(2):168-178
Bioassays were adapted to investigate effects of droplet size and carrier volume on performance of daminozide, gibberellic acid (GA3) and 2,4-D using Phaseolus vulgaris L. as a model system. Response to plant growth regulators was indexed by inhibition (daminozide), promotion of internode elongation (GA3) or ethylene production (2,4-D). Elongation of first plus second internodes above primary leaves was evaluated 14 days after treatment of primary leaves, while ethylene production was determined from head-space samples of incubated leaves 24 h after treatment. Daminozide inhibition of internode elongation was related to decreased cell size and number in pith and epidermis (range 49–70% of the untreated control). GA3 increased cell size and number in both tissues 2·3- to 4·8-fold. Responsiveness to daminozide and 2,4-D markedly decreased as seedling age increased from 8 to 12 days, but responsiveness to GA3 increased. Decreasing droplet size (10–0·5 μl) and increasing carrier volume (10–200 μl per leaf) at constant dose of daminozide (100 μg per leaf) and 2,4-D (100 μg per leaf) significantly increased performance, but had little effect on performance of GA3 (2 μg per leaf). Effects of application factors on performance were related to their effects on the interface area between droplets and leaf surface. Significant positive linear relationships were obtained between plant response and the logarithm of the droplet/leaf interface area for all growth regulators. © 1998 Society of Chemical Industry 相似文献
58.
Kevan J. Williams C. Richard James Stephen A. Thorpe Stewart L. Reynolds 《Pest management science》1997,50(2):135-140
Two analytical methods are presented for the determination of 2,4-D in oranges. The screening procedure uses a commercial ELISA kit, designed for the determination of 2,4-D in water. Good semi-quantitative screening data were obtained provided that the standard solutions used to construct the calibration curve were prepared in blank orange extract. The limited quantification range of the kit was due to the narrow linear range and differences in response to 2,4-D when present as the free acid and as various esters. A GC-MS confirmatory technique involved extraction of 2,4-D from oranges by homogenisation with methanol, filtration and esterification/transesterification with boron trifluoride-methanol. Recoveries for three spiking levels (0·2, 1·0 and 2·0 mg kg-1) for 2,4-D and 2,4-D isopropyl ester were within the range 75–120%. In a small survey of retail oranges, 10 samples were screened using the ELISA kit and four were found to have >0·2 mg 2,4-D kg-1. All four residues were confirmed by GC-MS. The ELISA procedure involves approximately half the staff effort of the GC-MS procedure. © 1997 SCI. 相似文献
59.
The transformations of eight herbicides (atrazine, simazine, terbutryn, pendimethalin, carbetamide, 2,4-D, metsulfuron-methyl and dimefuron) in soil after compost addition were monitored during long-term laboratory incubations. The herbicides were applied to soil, compost and soil-compost mixtures. Herbicide sorption, their kinetics of mineralisation and the extractability of residues were compared in the different treatments. Compost addition to soil generally decreased herbicide mineralisation and favoured the stabilisation of herbicide residues. A fraction of the stabilised residues remained extractable and potentially available. However, most of them were unextractable and formed bound residues. Sorption could be at the origin of a kinetically limited biodegradation, mainly for the most highly-sorbed herbicides (atrazine, simazine, terbutryn, pendimethalin and dimefuron). Compost addition had little effects on the less sorbed herbicides (carbetamide, 2,4-D and metsulfuron- methyl). © 1997 SCI. 相似文献
60.
Adsorption–desorption characteristics of 2,4-dichlorophenoxyacetic acid (2,4-D) on pure montmorillonite and synthetic chlorite-like complexes [Al(OH)x-montmorillonite complexes, obtained by coating montmorillonite surfaces with different amounts of Al(OH)x] were investigated. The equilibrium adsorption of 2,4-D was described by both Langmuir and Freundlich type isotherms. The extent of adsorption as well as the type of interaction between adsorbate and adsorbent was affected by the nature of incubation buffer and the charge characteristics of supports. At pH 5·6 and in acetate buffer, 2,4-D was negatively adsorbed by montmorillonite and herbicide adsorption capacity increased with increasing amounts of Al(OH)x species loaded on montmorillonite surfaces. When adsorption experiments were performed at the same pH but in phosphate buffer, strong reductions of both the amount of adsorbed pesticide and its affinity for the adsorbents were measured. Evidently, phosphate anions competed strongly with 2,4-D anions for the sorption site on chlorite-like complexes. Furthermore, desorption tests revealed that a large amount (about 60%) of the pesticide was firmly bound to the clay and was not removed even after repeated washings or 24 h exposure to desorption solution. Both electrostatic interactions between the negative COO- moieties of 2,4-D and the positive sites on clays, and ligand exchanges of COO- groups with -OH or water at the clay surface were probably involved in the adsorption process. ©1997 SCI 相似文献