共查询到20条相似文献,搜索用时 734 毫秒
1.
Takashi Haramura 《Journal of Ethology》2007,25(1):3-7
Microhabitat selection is particularly important to increase the survival rate and reproductive success of animals inhabiting
heterogeneous environments. I investigated microhabitat selection of Buergeria
japonica tadpoles inhabiting the stream in a coastal area to reveal how animals select their appropriate habitat under heterogeneous
and unstable environments on the subtropical Okinawa Island of Japan. Tadpoles are sensitive to subtle environmental changes,
and the mouths of streams in coastal areas that have intense environmental fluctuations such as desiccation and sudden changes
in current velocity would be risky habitat for tadpoles. Tadpoles of B. japonica can inhabit both lotic and lentic systems. Field observations showed that, among six physical factors (water depth, water
temperature, salinity, pH, current velocity, and substrate), current velocity and water temperature were key factors in microhabitat
selection by tadpoles. It is likely that tadpoles stay at low current velocity sites to reduce the probability of being washed
out to the sea by a sudden squall and that selection of warmer sites would accelerate development of tadpoles so as to escape
the heterogeneous aquatic habitat sooner. 相似文献
2.
Lateral line-mediated rheotactic behavior in tadpoles of the African clawed frog (<Emphasis Type="Italic">Xenopus laevis</Emphasis>) 总被引:3,自引:0,他引:3
Tadpoles (Xenopus laevis) have a lateral line system whose anatomical structure has been described, but whose functional significance has not been closely examined. These experiments tested the hypothesis that the lateral line system is involved in rheotaxis. Tadpoles in developmental stages 47–56 oriented toward the source of a water current. Orientation was less precise after treatment with cobalt chloride or streptomycin, but was similar to that of untreated animals after exposure to gentamicin. In no current conditions, tadpoles exhibited a characteristic head-down posture by which they held themselves in the water column at an angle around 45°. This body posture became significantly less tilted in the presence of water current. Treatment with cobalt chloride or streptomycin increased the angle of tilt close to that seen in no current conditions, while gentamicin treatment tended to decrease tilt angle. The data are consistent with anatomical and physiological findings that tadpole neuromasts are similar to superficial, but not canal, neuromasts in fishes, and they suggest that the lateral line system is involved in both directional current detection and current-related postural adjustments in Xenopus. 相似文献
3.
The survival of Cryptosporidium parvum oocysts in a waste stabilization pond system in northwestern Spain and the effects of sunlight and the depth and type of
pond on oocyst viability were evaluated using an assay based on the exclusion or inclusion of two fluorogenic vital dyes,
4′,6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI). All tested factors had significant effects (P < 0.01) over time on C. parvum oocyst viability. Sunlight exposure was the most influential factor for oocyst inactivation. A 40% reduction was observed
after 4 days exposure to sunlight conditions compared with dark conditions. The type of pond also caused a significant reduction
in C. parvum oocyst viability (P < 0.01). Inactivation rates reflected that the facultative pond was the most aggressive environment for oocysts placed both
at the surface (presence of sunlight) and at the bottom (absence of sunlight) of the pond, followed by the maturation pond
and the anaerobic pond. The mean inactivation rates of oocysts in the ponds ranged from 0.0159 to 0.3025 day−1. 相似文献
4.
This is the first report of North American bullfrogs, Lithobates catesbeianus (=Rana catesbeiana), invasion in Uruguay. This Anura was introduced for farming proposes in 1987, but at present most of the farms are closed.
At one of these closed farms, located at Rincón de Pando, Canelones, we report the occurrence of a feral population of L. catesbeianus. This invasion point is at an early stage and restricted to one or two ponds. We also report the effects of L. catesbeianus invasion in the community structure. This includes species composition and species size structure. In this system bullfrog
tadpoles constitute a very important proportion of the present biomass. Bullfrog tadpoles appear to be displacing native amphibians
and having some type of positive interaction with fishes. At the invaded system we found more fish species and larger sizes
of the shared fish species. We analyze the involved risks of this invasion, the ecological impact by predation, the competition
and habitat modification, and the potential of bullfrog to act as pathogens vector. We also recommend taking measures in order
to avoid the expansion of this population. There is also the need of studies to search for new invasion points in Uruguay,
especially where bullfrog farms were located. 相似文献
5.
We investigated the occurrence pattern of the pond-living endangered cyprinid, Pseudorasbora pumila, and also compared its habitat characteristics with those of the congeneric invasive species, Pseudorasbora parva, in the contact zone. Comparison of 16 environmental variables among the P. pumila habitats, P. parva habitats, and unoccupied ponds revealed that conductivity was a common limitation factor of distribution of both species.
We found that emergent vegetation occupancy along the pond bank was the most important factor determining P. pumila occurrence and that ponds with steep banks may have a low probability of containing P. parva. We constructed a logistic regression model to predict the establishment risk of P. parva in ponds occupied by P. pumila. The model demonstrated that more than half of the ponds exhibited a high establishment risk of P. parva. Principal component analysis using six parameters selected from stepwise logistic regression analysis revealed that seven
unoccupied ponds had the potential to sustain P. pumila, suggesting that our study site is capable of supporting more P. pumila populations and expanding the current range. 相似文献
6.
N. M. Usmanova S. N. Litvinchuk E. A. Kazakova V. I. Kazakov 《Cell and Tissue Biology》2010,4(5):436-441
The variable microsatellite repeat BM224 has been revealed in the genomes of eight species of green frogs (Rana ridibunda, R. cf. bedriagae, R. cretensis, R. esculenta, R. lessonae, R. shquiperica, R. saharica, R. nigromaculata). Previously, this repeat was observed in members of the genus Bufo. In this paper, the possibility of using this genetic marker for species identification is discussed. 相似文献
7.
M. W. Brown 《BioControl》2011,56(1):65-69
The biological control of aphid populations may only be possible when natural enemies arrive soon after aphid colonization.
This study was done to identify how quickly adult Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) need to arrive at newly established spirea aphid [Aphis spiraecola Patch (Homoptera: Aphididae)] colonies on apple (Malus domestica Borkh.) to provide population control. A total of 100 newly established spirea aphid colonies were caged in an experimental
apple orchard in West Virginia, USA. A single adult H. axyridis was added to each of ten caged colonies at day 0, 5, 10, 15 and 20 days after caging. An additional ten caged colonies were
opened for exposure to natural levels of predation at each of the treatment intervals as a control. The single H. axyridis eliminated the aphid colonies significantly more quickly than natural predation for up to ten days after colony establishment.
The probability of an aphid colony producing alates was significantly lower in the presence of a single H. axyridis adult than when exposed to natural predation for the first ten days. Adult H. axyridis beetles are capable of completely controlling individual spirea aphid colonies on apple only if they are abundant enough
to find colonies within one week of colony establishment. 相似文献
8.
We isolated the full-length cDNAs of engrailed and dpp-BMP2/4 orthologues from the pond snail Lymnaea stagnalis and examined their expression patterns during development by the whole mount in situ hybridization. At the gastrula and trochophore
stages, engrailed is expressed in the peripheral ectoderm of the presumptive and invaginating shell gland, corroborating its role in the shell
formation that is widely conserved among molluscs. At the same stages, dpp-BMP2/4 is expressed in the right-hand side ectoderm of the shell gland and in the invaginating stomodaeum. Unlike in the gastropod
Patella vulgata, our results suggested that dpp-BMP2/4 has a role in the shell formation, rather than in the regional specification and that it could be involved in the specification
pathway of the left–right asymmetry of the developing shell in L. stagnalis. 相似文献
9.
The extremely halophilic bacterium Salinibacter ruber inhabits saltern crystallizer ponds worldwide, together with the square archaeon Haloquadratum walsbyi. Cultures of Salinibacter have been shown to convert up to 20% of the glycerol added to a not previously characterized overflow product. We here identify
this product of incomplete glycerol oxidation by Salinibacter as dihydroxyacetone. Genomic information suggests that H. walsbyi possesses an efficient uptake system for dihydroxyacetone, and we show here that dihydroxyacetone is indeed metabolized by
Haloquadratum cultures, as well as by the heterotrophic prokaryotic community of the saltern crystallizer ponds in Eilat, Israel, dominated
by Haloquadratum-like cells. In the absence of glycerol, Salinibacter also takes up dihydroxyacetone. Degradation of glycerol, produced in hypersaline lakes as an osmotic solute by the green
alga Dunaliella salina may thus involve dihydroxyacetone as an intermediate, which can then be taken up by different types of heterotrophs present
in the environment. 相似文献
10.
Wildling S Kerschbaum HH 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2007,177(4):401-411
In the present study, we quantified the physiological consequences of nitric oxide (NO) on ammonium release in tadpoles of
Xenopus laevis. Tadpoles exposed to S-nitro-N-acetylpenicillamine (SNAP), an NO-donor, or l-arginine, the substrate of NO synthase (NOS), showed a reversible decrease, whereas animals exposed to the NOS inhibitor Nω-methyl-l-arginine (l-NMMA) exhibited an increase in ammonium release. Release of ammonium may be of physiological relevance during stress response
of the animal. Handling of tadpoles as well as exposure to hyposmotic environments increased ammonium release. To localize
NO synthesizing cells, we used diaminofluorescein-diacetate (DAF-2DA), an NO-sensitive fluorescent dye, and NADPH-diaphorase
histochemistry, an indicator for NOS activity. We observed a fluorescence signal as well as NADPH-diaphorase activity in small,
solitary cells in the epidermis. Similarly to NADPH-diaphorase histochemistry, silver nitrate staining and rhodamine labelling,
markers for mitochondria-rich cells, showed a strong reaction in these cells. These observations indicate that NO (1) inhibits
ammonium release, and (2) is endogenously synthesized in mitochondria-rich cells in Xenopus tadpoles. Based on our histochemical results, we speculate that gill epithelium and epidermis work in parallel to release
ammonium as epidermal tissue contains mitochondria-rich and NADPH-diaphorase positive cells. 相似文献
11.
Makoto Urata Jun Tsuchimoto Kinya Yasui Masaaki Yamaguchi 《Development genes and evolution》2009,219(7):377-382
Deuterostomes comprise a monophyletic group of animals that include chordates, xenoturbellids, and the Ambulacraria, which
consists of echinoderms and hemichordates. The ancestral chordate probably had 14 Hox genes aligned linearly along the chromosome, with the posterior six genes showing an independent duplication compared to
protostomes. In contrast, ambulacrarians are characterized by a duplication of the posterior Hox genes, resulting in three genes known as Hox11/13a, Hox11/13b, and Hox11/13c. Here, we isolated 12 Hox genes from the hemichordate Balanoglossus misakiensis and found an extra Hox gene that has not been reported in hemichordates. The extra B. misakiensis gene was suggested to be Hox8 from paralog-characteristic residues in its hexapepetide motif and homeodomain and a comparison with Strongylocentrotus purpuratus Hox genes. Our data suggest that the ancestor of echinoderms and hemichordates may have had a full complement of 12 Hox genes. 相似文献
12.
13.
A study was conducted in Xiangshan Bay, Ningbo, China, using red alga Gracilaria lichenoides to alleviate nutrient pollution in shrimp (Litopenaeus vannamei) and fish (Epinephelus awoara) culture ponds. Our results showed that G. lichenoides was efficient at absorbing inorganic nitrogen (IN) and inorganic phosphate (IP), and maintained a more stable dissolved oxygen
(DO) level. A total of 506.5 kg (1,013 kg ha−1) of shrimp and 210.5 kg (421 kg ha−1) of fish were harvested from the shrimp/algae (SA) and fish/algae (FA) ponds, respectively. Only 53.5 kg shrimp were harvested
from the shrimp pond without Gracilaria (S) due to anoxic asphyxia, and 163 kg fish were harvested from the fish culture pond without Gracilaria (F). Compared with using microalgae, bioremediation by macroalgae has no risk of harmful algal blooms (HABs), and it is easy
to control seaweed biomass. During the experiment, there was a better environmental condition (lower chemical oxygen demand,
IN, IP and chlorophyll a concentrations) in the ponds with Gracilaria. Furthermore, Gracilaria spp. can be used as food for abalone or other aquacultured animals and thus enhance economic return. 相似文献
14.
The study assessed the composition and abundance of insect assemblages associated with two submerged macrophytes, Lagarosiphon ilicifolius and Vallisneria aethiopica, in fishless ponds. Six ponds were used, with each plant occurring singly in two ponds, whilst the remainder had both plants.
The insects were sampled using a 500-μm mesh. The number of insect taxa, diversity and total abundance on Lagarosiphon were greater than on Vallisneria when the plants occurred in separate ponds. In ponds comprising both plants, the total insect abundance on Lagarosiphon was greater than on Vallisneria. In all ponds, anisopteran naiads were dominant. Hemicordulia, Diplacodes and Trithemis made up 36.2, 27.1 and 15.2%, respectively, of the total number of insects on Lagarosiphon in single plant ponds. Trithemis was the only odonate in ponds comprised exclusively of Vallisneria and made up 68.7% of insects. In ponds that were cultured with both plants, four anisopteran taxa, Hemicordulia, Diplacodes, Trithemis and Tramea, were collected. In single plant ponds, the body-size class distribution of naiads on Lagarosiphon was characterised by a broader range, with significantly greater numbers of smaller and larger size classes than on Vallisneria (Kolmogorov–Smirnov test, P < 0.05). The study shows that in fishless waters, epiphytic insect assemblages may differ between the two plant species,
especially when they are widely separated in space, probably due to greater predator–prey interactions on Vallisneria than on Lagarosiphon. The two plants may also differentially affect water physicochemical conditions, which may possibly influence insect ovipositing
behaviour, and so affect insect community assemblage. 相似文献
15.
The enduring toxicity of road-killed cane toads (<Emphasis Type="Italic">Rhinella marina</Emphasis>)
The primary ecological impact of invasive cane toads (Rhinella marina) in Australia is mediated by their powerful toxins, which are fatal to many native species. Toads use roads as invasion corridors
and feeding sites, resulting in frequent road-kills. The flattened, desiccated toad carcasses remain highly toxic despite
being heated daily to >40°C for many months during the tropical dry-season. In controlled laboratory experiments, native tadpoles
(Cyclorana australis, Litoria rothii), fishes (Mogurnda mogurnda) and leeches (Family Erpobdellidae) died rapidly when we added fragments of sun-dried toad to their water, even if the native
animals had no physical access to the carcass. Given the opportunity, native tadpoles and fishes strongly avoided the vicinity
of dried toad fragments. Hence, long-dead toads may contaminate roadside ponds formed by early wet-season rains and induce
avoidance and/or mortality of native anuran larvae, fishes and invertebrates. Our studies show that the toxicity of this invasive
species does not end with the toad’s death, and that methods for disposing of toad carcasses (e.g., after culling operations)
need to recognize the persistent danger posed by those carcasses. 相似文献
16.
17.
Nouioui I Ghodhbane-Gtari F Beauchemin NJ Tisa LS Gtari M 《Antonie van Leeuwenhoek》2011,100(4):579-587
To construct an evolutionary hypothesis for the genus Frankia, gyrB (encoding gyrase B), nifH (encoding nitrogenase reductase) and glnII (encoding glutamine synthetase II) gene sequences were considered for 38 strains. The overall clustering pattern among
Frankia strains based on the three analyzed sequences varied among themselves and with the previously established 16S rRNA gene phylogeny
and they did not reliably reflect clear evolution of the four discerned Frankia clusters (1, 2, 3 and 4). Based on concatenated gyrB, nifH and glnII, robust phylogenetic trees were observed with the three treeing methods (Maximum Likelihood, Parsimony and Neighbor-Joining)
and supported by strong bootstrap and posterior probability values (>75%) for overall branching. Cluster 4 (non-infective
and/or non-nitrogen-fixing Frankia) was positioned at a deeper branch followed by cluster 3 (Rhamnaceae and Elaeagnaceae infective Frankia), while cluster 2 represents uncultured Frankia microsymbionts of the Coriariaceae, Datiscaceae, Rosaceae and of Ceanothus sp. (Rhamnaceae); Cluster 1 (Betulaceae, Myricaceae and Casuarinaceae infective Frankia) appears to have diverged more recently. The present study demonstrates the utility of phylogenetic analyses based upon concatenated
gyrB, nifH and glnII sequences to help resolve previously unresolved or poorly resolved nodes and will aid in describing species among the genus
Frankia. 相似文献
18.
S. A. Kopyl N. V. Dorogova E. M. Akhmametyeva L. V. Omelyanchuk L. -S. Chang 《Russian Journal of Genetics》2010,46(3):276-282
The protein Merlin is involved in the regulation of cell proliferation and differentiation in the eyes and wings of Drosophila and is a homolog of the human protein encoded by the Neurofibromatosis 2 (NF2) gene whose mutations cause auricular nerve tumors. Recent studies show that Merlin and Expanded cooperatively regulate the
recycling of membrane receptors, such as the epidermal growth factor receptor (EGFR). By performing a search for potential
genetic interactions between Merlin (Mer) and the genes important for vesicular trafficking, we found that ectopic expression in the wing pouch of the clathrin adapter
protein Lap involved in clathrin-mediated receptor endocytosis resulted in the formation of extra vein materials. On the one
hand, coexpression of wild-type Merlin and lap in the wing pouch restored normal venation, while overexpression of a dominant-negative mutant Mer
DBB
together with lap enhanced ectopic vein formation. Using various constructs with Merlin truncated copies, we showed the C-terminal portion
of the Merlin protein to be responsible for the Merlin-lap genetic interaction. Furthermore, we showed that the Merlin and Lap proteins colocalized at the cortex of the wing imaginal
disc cells. 相似文献
19.
Rahel Elevi Bardavid Danny Ionescu Aharon Oren Fred A. Rainey Becky J. Hollen Danielle R. Bagaley Alanna M. Small Christopher McKay 《Hydrobiologia》2007,576(1):3-13
Salinibacter is a genus of red, extremely halophilic Bacteria. Thus far the genus is represented by a single species, Salinibacter ruber, strains of which have been isolated from saltern crystallizer ponds in Spain and on the Balearic Islands. Both with respect
to its growth conditions and its physiology, Salinibacter resembles the halophilic Archaea of the order Halobacteriales. We have designed selective enrichment and isolation techniques to obtain Salinibacter and related red extremely halophilic Bacteria from different hypersaline environments, based on their resistance to anisomycin and bacitracin, two antibiotics that are
potent inhibitors of the halophilic Archaea. Using direct plating on media containing bacitracin, we found Salinibacter-like organisms in numbers between 1.4×103 and 1.4×106ml−1 in brines collected from the crystallizer ponds of the salterns in Eilat, Israel, being equivalent to 1.8–18% of the total
colony counts obtained on identical media without bacitracin. A number of strains from Eilat were subjected to a preliminary
characterization, and they proved similar to the type strain of S. ruber. We also report here the isolation and molecular detection of Salinibacter-like organisms from an evaporite crust on the bottom of salt pools at the Badwater site in Death Valley, CA. These isolates
and environmental 16S rRNA gene sequences differ in a number of properties from S. ruber, and they may represent a new species of Salinibacter or a new related genus.
Guest Editor: John M. Melack
Saline Waters and their Biota 相似文献
20.
Transposable elements are important factors driving plant genome evolution. Upon their mobilization, novel insertion polymorphisms
are being created. We investigated differences in copy number and insertion polymorphism of a group of Mariner-like transposable
elements Vulmar and related VulMITE miniature inverted-repeat transposable elements (MITEs) in species representing subfamily Betoideae. Insertion sites of these elements were identified using a modified transposon display protocol, allowing amplification of longer fragments representing
regions flanking insertion sites. Subsequently, a subset of TD fragments was converted into insertion site-based polymorphism
(ISBP) markers. The investigated group of transposable elements was the most abundant in accessions representing the section
Beta, showing intraspecific insertion polymorphisms likely resulting from their recent activity. In contrast, no unique insertions
were observed for species of the genus Beta section Corollinae, while a set of section-specific insertions was observed in the genus Patellifolia, however, only two of them were polymorphic between P. procumbens and P. webbiana. We hypothesize that Vulmar and VulMITE elements were inactivated in the section Corollinae, while they remained active in the section Beta and the genus Patellifolia. The ISBP markers generally confirmed the insertion patterns observed with TD markers, including presence of distinct subsets
of TE insertions specific to Beta and Patellifolia. 相似文献