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51.
Plasma cortisol concentrations before and after social stress in rainbow trout and brown trout 总被引:1,自引:0,他引:1
Sloman KA Metcalfe NB Taylor AC Gilmour KM 《Physiological and biochemical zoology : PBZ》2001,74(3):383-389
Two related experiments examined the relationship between plasma cortisol concentrations and the development of social hierarchies in fish. In the first, rainbow trout, Oncorhynchus mykiss, and brown trout, Salmo trutta, were observed for dominance interactions when confined within single-species pairs for 4, 48, or 168 h. Subordinate members of a pair exhibited significantly higher cortisol concentrations than dominant and single fish, but the pattern of cortisol elevation differed between the two species, being quicker to rise and increasing to a higher level in rainbow trout. Cortisol concentrations were correlated with behavioural measurements; the more subordinate the behaviour exhibited by a fish, the higher its cortisol concentration. Social stress was a chronic stressor, and no acclimation to social status occurred during the week. In the second experiment, measurements of plasma cortisol were made before pairing of rainbow trout and then after 48 h of confinement in pairs. Subordinate fish demonstrated significantly higher concentrations of plasma cortisol both before and after social stress. It therefore appears that in addition to cortisol being elevated during periods of social stress, an association may exist between initial cortisol levels and the likelihood of a fish becoming subordinate. 相似文献
52.
Phylogenetic utility of the nuclear gene arginine decarboxylase: an example from Brassicaceae 总被引:10,自引:2,他引:8
Arginine decarboxylase (ADC) is an important enzyme in the production of
putrescine and polyamines in plants. It is encoded by a single or low-copy
nuclear gene that lacks introns in sequences studied to date. The rate of
Adc amino acid sequence evolution is similar to that of ndhF for the
angiosperm family studied. Highly conserved regions provide several target
sites for PCR priming and sequencing and aid in nucleotide and amino acid
sequence alignment across a range of taxonomic levels, while a variable
region provides an increased number of potentially informative characters
relative to ndhF for the taxa surveyed. The utility of the Adc gene in
plant molecular systematic studies is demonstrated by analysis of its
partial nucleotide sequences obtained from 13 representatives of
Brassicaceae and 3 outgroup taxa, 2 from the mustard oil clade (order
Capparales) and 1 from the related order Malvales. Two copies of the Adc
gene, Adc1 and Adc2, are found in all members of the Brassicaceae studied
to data except the basal genus Aethionema. The resulting Adc gene tree
provides robust phylogenetic data regarding relationships within the
complex mustard family, as well as independent support for proposed tribal
realignments based on other molecular data sets such as those from
chloroplast DNA.
相似文献
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Karine Salin Sonya K. Auer Agata M. Rudolf Graeme J. Anderson Andrew G. Cairns William Mullen Richard C. Hartley Colin Selman Neil B. Metcalfe 《Biology letters》2015,11(9)
There is increasing interest in the effect of energy metabolism on oxidative stress, but much ambiguity over the relationship between the rate of oxygen consumption and the generation of reactive oxygen species (ROS). Production of ROS (such as hydrogen peroxide, H2O2) in the mitochondria is primarily inferred indirectly from measurements in vitro, which may not reflect actual ROS production in living animals. Here, we measured in vivo H2O2 content using the recently developed MitoB probe that becomes concentrated in the mitochondria of living organisms, where it is converted by H2O2 into an alternative form termed MitoP; the ratio of MitoP/MitoB indicates the level of mitochondrial H2O2
in vivo. Using the brown trout Salmo trutta, we tested whether this measurement of in vivo H2O2 content over a 24 h-period was related to interindividual variation in standard metabolic rate (SMR). We showed that the H2O2 content varied up to 26-fold among fish of the same age and under identical environmental conditions and nutritional states. Interindividual variation in H2O2 content was unrelated to mitochondrial density but was significantly associated with SMR: fish with a higher mass-independent SMR had a lower level of H2O2. The mechanism underlying this observed relationship between SMR and in vivo H2O2 content requires further investigation, but may implicate mitochondrial uncoupling which can simultaneously increase SMR but reduce ROS production. To our knowledge, this is the first study in living organisms to show that individuals with higher oxygen consumption rates can actually have lower levels of H2O2. 相似文献
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Testosterone induced papillomata in 85% (11/13) of initially non-papillomatous white suckers Catostomus commersoni and increased papillomata growth in 100% (16/16) of initially papillomatous suckers. 17β-oestradiol induced papillomata in 83% (10/12) of initially nonpapillomatous suckers and increased papillomata growth in 100% (16/16) of initially papillomatous suckers. Less than 29% (4/14) of white suckers injected with tamoxifen developed papillomata, while complete papillomata regression was observed in 71% (10/14) of initially papillomatous suckers. In control groups 59% (27/46) of suckers either retained or developed papillomata and 27% (6/24) of suckers exhibited tumour regression. Protein kinase C (PKC) activity was significantly depressed and ornithine decarboxylase (ODC) activity was significantly elevated in steroid-treated papillomata v. normal lip epidermis. ODC activity was significantly depressed in tamoxifen-injected, regressing papillomata. There were no significant differences in plasma oestrogen and testosterone levels between papillomatous and nonpapillomatous female fish from a site contaminated with persistent organic chemicals and an uncontaminated reference site. Similarly, no significant differences in testosterone and 11-ketotestosterone levels were observed between papillomatous and non-papillomatous male fish. 相似文献
59.
Amphibiobeania epiphylla is a new, monotypic taxon of Beaniidae (Cheilostomata) from Darwin, Northern Territory. It is unique among the 6,000 living species of Bryozoa in that it encrusts mainly living tree leaves (chiefly the mangrove Rhizophora stylosa). The consequence of living in such a specialized habitat is that colonies are emergent (subaerial) for a significant part of the tidal cycle-around 12 of every 24 hours during spring tides and for several days during neap tides. Desiccation is prevented or minimized by the high humidity of the habitat and a cohesive coating of silt covering the colony. Zooids are weakly calcified and lie alternately on their left and right sides in a lineal series, with opercula displaced to the outer corner of the distal zooidal rim. Organisms associated with A. epiphylla include a colony-damaging ceratopogonid (Diptera) larva and a tarsonemid mite that may use dead zooidal interiors, beneath the silt crust, for shelter. 相似文献
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