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1.
Entrapments of whales in sea ice occur occasionally in the Arctic and often last several weeks or months, resulting in emaciation or death of whales. These events provide a unique opportunity for investigating the physiological response to a prolonged or chronic stress in an otherwise healthy population of marine mammals. By measuring cortisol in blubber, a peripheral tissue, we expect to see a reflection of long-term or chronic stress rather than short-term or acute stress. Adipose tissue should be less subject to rapid changes compared to blood cortisol, reflecting stressors experienced over a longer period of time, and should not be affected by potential stress associated with sampling. We measured blubber cortisol of 29 beluga whales (Delphinapterus leucas) entrapped in November 2006 in Husky Lakes basin and 26 whales from the same population (Eastern Beaufort Sea) during regular seasonal harvests in July of 2006 and 2007. Mean cortisol concentrations (±SEM) were seven times higher in blubber from entrapped whales (1.76 ± 0.32 ng/g wet weight) compared to whales from regular seasonal harvests (0.26 ± 0.042 ng/g wet weight) and appeared to increase with whale age. Our results provide a measure of blubber cortisol from a prolonged stress and demonstrate blubber cortisol as a useful indicator of longer-term exposure to stress in beluga whales.  相似文献   

2.
The periods of development individual behavior in beluga calves are described. During these periods, calves form locomotor skills and interrelations with other individuals, and this determines the overall social structure of a pod. The formation of behavior in White Sea beluga calves passes through a number of stages. New types of social interactions arose in the following sequence: the imprinting period, the first abandoning of the mother without contact with other members of the pod and accumulation of new locomotive elements, first contacts with other young-of-the-year calves, and the complication of interaction types through game activities. Calves usually formed pairs with coevals or elder calves that possessed a richer locomotor repertoire. New motions appeared as a result of imitation of adult animals. These periods do not have distinct terms and depend on the individual qualities of the calves. Some changes in the belugas’ behavior were seen under the conditions of the active development of managed ecotourism in the area around Solovetsky Island, the animals showed adaptation to the presence of man.  相似文献   

3.
Seasonal migrations of beluga whales from the Sakhalin-Amur aggregation in the Sea of Okhotsk were investigated with the use of satellite telemetry. Satellite tags were attached to four females captured near Chkalova Island, Sakhalin Bay, in August 2007. At 5 weeks after tagging, the belugas left the Chkalova Island area and moved to the Nikolaya and Ul’banskii Bays in the Shantar Sea. The animals stayed in these bays (mainly in Nikolaya Bay) until the end of autumn and then traveled northward to deeper waters. In winter and spring, they preferred to stay in the regions with dense ice cover or close to the ice edge. During the winter migration, the tagged whales, as a rule, did not keep together, although they followed the same course with a little time lag. The female whose tag transmitted the longest (9.5 months) returned to Chkalova Island in late May and thus completed the seasonal migration cycle. Based on the data on the migration routes of the tagged belugas, we suggest that the Sakhalin-Amur and Shantar aggregations interact in autumn. It is also possible that they have similar winter migratory paths  相似文献   

4.
The spectral parameters of heart rate variability are a measure of activation of the sympathetic and parasympathetic branches of the mammalian autonomic nervous system. In this study, spectral analysis was used for the first time to evaluate the impact of acoustic noise (one of the major anthropogenic factors) on a cetacean. We analyzed cardiac intervals in a captive beluga (a member of the Odontoceti whales) in response to a 10-min band-pass acoustic noise at an intensity of 150–165 dB and frequency of 19–38 kHz. The beluga’s response to acoustic noise, when examined shortly after the animal’s capture, was characterized by a sharp tachycardia (the first phase) followed by a decrease in the heart rate (the second phase). Based on spectral analysis, the frequency range of heart rate oscillations in the beluga decreased during the period of tachycardia while shifting to a lower frequency range (below 0.01 Hz) as compared with the control conditions. Accordingly, the spectral power of low-frequency components was reduced. During the second phase, the range of heart rate variability oscillations expanded and fully recovered only after the noise had been turned off. After one year in captivity, no significant changes in the heart rate parameters (both in time and frequency domain) were recorded in response to a similar noise exposure. Therefore, the changes in the heart rate spectral components in the studied beluga exposed to acoustic noise were comparable to those recorded in terrestrial mammals and in humans in stressful and emotionally negative situations. The spectral characteristics of heart rate oscillations can be used as a quantitative measure of beluga whales’ response to acoustic noise as a stress factor.  相似文献   

5.
The data on mtDNA sequences of the beluga whale (Delphinapterus leucas) from the central Eastern Arctic as well as coastal waters of the Chukchi Peninsula and different parts of the White Sea are presented and analyzed for the first time. Certain sequences found in the region form a separate phylogenetic clade. The distinctness of composition of maternal lineages found for the White Sea is noted. However, the set of sequences found in the Russian Arctic in whole cannot be characterized as region-specific.  相似文献   

6.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.  相似文献   

7.
New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.  相似文献   

8.
Traditionally viewed as an Andean grain crop,Chenopodium quinoa Willd. includes domesticated populations that are not Andean, and Andean populations that are not domesticated. Comparative analysis of leaf morphology and allozyme frequencies have demonstrated that Andean populations, both domesticated(quinua) and free-living(ajara), represent an exceptionally homogeneous unit that is well differentiated from allied domesticates of coastal Chile(quingua) and freeliving populations of the Argentine lowlands(C. hircinum). This pattern of relationships indicates that Andean populations represent a monophyletic crop/weed system that has possibly developed through cyclic differentiation (natural vs. human selection) and introgressive hybridization. Relative levels of variation suggest that this complex originated in the southern Andes, possibly from wild types allied withC. hircinum, with subsequent dispersal north to Colombia and south to the Chilean coast. Coastal populations were apparently isolated from post-dispersal differentiation and homogenization that occurred in the Andes. Other data point toward a center of origin in the northern Andes with secondary centers of genetic diversity subsequently developing in the southern Andes and the plains of Argentina. Comparative linkage of South American taxa, all tetraploid, with North American tetraploids of the subsection will eventually clarify this problem. While the possibility of a direct phyletic connection betweenC. quinoa and the Mexican domesticate(C. berlandieri subsp. nuttalliae,) cannot be excluded, available evidence indicates that the latter represents an autonomous lineage that is associated with the basal tetraploid, C. b. subsp.berlandieri, through var.sinuatum, whereas South American taxa show possible affinities to either var. zschackei or var.berlandieri. An extinct domesticate of eastern North America,C. b. subsp.jonesianum, represents either another instance of independent domestication, possibly from subsp. b. var.zschackei, or a northeastern outlier of subsp.nuttalliae.  相似文献   

9.
We have investigated the floral ontogeny of Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis (of the eucalypt group, Myrtaceae) using scanning electron microscopy and light microscopy. Several critical characters for establishing relationships between these genera and to the eucalypts have been determined. The absence of compound petaline primordia in Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis excludes these taxa from the eucalypt clade. Post-anthesis circumscissile abscission of the hypanthium above the ovary in Stockwellia, Eucalyptopsis and Allosyncarpia is evidence that these three taxa form a monophyletic group; undifferentiated perianth parts and elongated fusiform buds are characters that unite Stockwellia and Eucalyptopsis as sister taxa. No floral characters clearly associate Arillastrum with either the eucalypt clade or the clade of Stockwellia, Eucalyptopsis and Allosyncarpia.We gratefully acknowledge Clyde Dunlop and Bob Harwood (Northern Territory Herbarium) for collecting specimens of Allosyncarpia, and Bruce Gray (Atherton) for collecting specimens of Stockwellia. The Australian National Herbarium (CANB) kindly lent herbarium specimens of Eucalyptopsis for examination. This research was supported by a University of Melbourne Research Development Grant to Andrew Drinnan.  相似文献   

10.

Background

Gonadotropin releasing hormone (GnRH) is responsible for stimulation of gonadotropic hormone (GtH) in the hypothalamus-pituitary-gonadal axis (HPG). The regulatory mechanisms responsible for brain specificity make the promoter attractive for in silico analysis and reporter gene studies in zebrafish (Danio rerio).

Results

We have characterized a zebrafish [Trp7, Leu8] or salmon (s) GnRH variant, gnrh 3. The gene includes a 1.6 Kb upstream regulatory region and displays the conserved structure of 4 exons and 3 introns, as seen in other species. An in silico defined enhancer at -976 in the zebrafish promoter, containing adjacent binding sites for Oct-1, CREB and Sp1, was predicted in 2 mammalian and 5 teleost GnRH promoters. Reporter gene studies confirmed the importance of this enhancer for cell specific expression in zebrafish. Interestingly the promoter of human GnRH-I, known as mammalian GnRH (mGnRH), was shown capable of driving cell specific reporter gene expression in transgenic zebrafish.

Conclusions

The characterized zebrafish Gnrh3 decapeptide exhibits complete homology to the Atlantic salmon (Salmo salar) GnRH-III variant. In silico analysis of mammalian and teleost GnRH promoters revealed a conserved enhancer possessing binding sites for Oct-1, CREB and Sp1. Transgenic and transient reporter gene expression in zebrafish larvae, confirmed the importance of the in silico defined zebrafish enhancer at -976. The capability of the human GnRH-I promoter of directing cell specific reporter gene expression in zebrafish supports orthology between GnRH-I and GnRH-III.
  相似文献   

11.
Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner. The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate larvae Galleria mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host.  相似文献   

12.
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.  相似文献   

13.
Single (unpaired) vegetative cells of freshwater pennate diatom Neidium cf. ampliatum differentiated into gametangia and produced a single zygote (auxospore) via a pedogamic process. The gametic nuclei fused after auxospore expansion had begun. The auxospore expanded in parallel to the apical axis of the gametangium.  相似文献   

14.
A genetic transformation system has been developed for callus cells of Crataegus aronia using Agrobacterium tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with 5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this is the first time to report an Agrobacterium-mediated transformation system in Crataegus aronia.  相似文献   

15.
Lin X  Minamisawa N  Takechi K  Zhang W  Sato H  Takio S  Tsukaya H  Takano H 《Planta》2008,228(4):601-608
ANGUSTIFOLIA (AN), a plant homolog of C-terminal binding protein, controls the polar elongation of leaf cells and the trichome-branching pattern in Arabidopsis thaliana. In the present study, degenerate PCR was used to isolate an ortholog of AN, referred to as LgAN, from larch (Larix gmelinii). The LgAN cDNA is predicted to encode a protein of 646 amino acids that shows striking sequence similarity to AN proteins from other plants. The predicted amino acid sequence has a conserved NAD-dependent 2-hydroxy acid dehydrogenase (D2-HDH) motif and a plant AN-specific LxCxE/D motif at its N-terminus, as well as a plant-specific long C-terminal region. The LgAN gene is a single-copy gene that is expressed in all larch tissues. Expression of the LgAN cDNA rescued the leaf width and trichome-branching pattern defects in the angustifolia-1 (an-1) mutant of Arabidopsis, showing that the LgAN gene has effects complementary to those of AN. These results suggest that the LgAN gene has the same function as the AN gene.  相似文献   

16.
Polystichum is one of the largest and most taxonomically complex fern genera in China. The evolutionary relationships of Chinese Polystichum and related genera, and the relationship between our Polystichum phylogeny and ecogeographic distribution, were tested by the use of DNA sequence data. Fifty-one species of Polystichum and 21 species in allied genera were sequenced for the plastid intergenic spacers rps4-trnS and trnL-F. Maximum parsimony and Bayesian phylogenetic analyses of both individual and combined data sets showed that Chinese Polystichum as commonly recognized was paraphyletic: one clade (the CCPC clade) included Cyrtomidictyum lepidocaulon, two Cyrtogonellum species, three Cyrtomium species, and a small number of Polystichum species usually occurring on limestone. A second clade, Polystichum sensu stricto, included the remainder of the Polystichum species; these often occur on non-limestone substrates. The remaining Cyrtomium species formed the third clade. Three subclades resolved within Polystichum sensu stricto (s.s.) clade do not correspond with recent sectional classifications, and we outline the issues relevant to a new classification for the genus. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

17.
The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.  相似文献   

18.
Previously, we described the unique feature of telomeric regions in Iberian shrew Sorex granarius: its telomeres have two ranges of size, very small (3.8 kb of telomeric repeats on average) and very large discontinuous telomeres (213 kb) interrupted with 18S rDNA. In this study, we have demonstrated extraordinary replication pattern of S. granarius large telomeres that have not been shown before in other studied mammal. Using the ReD-FISH procedure, we observed prolonged, through S period, large telomere replication. Furthermore, revealed ReD-FISH asymmetric signals were probably caused by partial replication of telomeres within an hour of 5-bromodeoxyuridine treatment due to the large size and special organization. We also found that in contrast to the telomeric halo from primary fibroblasts of bovine, mink, and common shrew, telomere halo of S. granarius consists of multiple loops bundled together, some of which contain rDNA. Here, we suggested several replicons firing possibly stochastic in each large telomere. Finally, we performed the TIF assay to reveal DNA damage responses at the telomeres, and along with TIF in nuclei, we found large bodies of telomeric DNA and ?-H2AX in the cytoplasm and on the surface of fibroblasts. We discuss the possibility of additional origin activation together with recombination-dependent replication pathways, mainly homologous recombination including BIR for replication fork stagnation overcoming and further S. granarius large telomere replication.  相似文献   

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