Search results for "juvenile"
showing 10 items of 366 documents
Developmental profiles of epidermal mRNAs during the pupal-adult molt of Tenebrio molitor and isolation of a cDNA clone encoding an adult cuticular p…
1992
0012-1606 (Print) Journal Article; Changes in translatable mRNAs from the wing epidermis of the Coleoptera Tenebrio molitor have been investigated during metamorphosis by analysis of in vitro translated products. Striking differences between the patterns obtained from mRNAs extracted during pupal and adult cuticle secretion indicated that a drastic change in gene expression occurs during the pupal-adult transition. In addition to these stage-specific modifications, the mRNA patterns changed within each cuticular synthesis program (pupal or adult), especially at ecdysis. After tritiated leucine incorporation, some of the major radiolabeled cuticular proteins showed similar changes suggesting…
Acetylcholinesterase activity in juvenileCiona intestinalis(Ascidiacea, Urochordata) after exposure to tributyltin
2012
The acetylcholinesterase (AChE) activity has been studied in 4-day post-fertilization juveniles of Ciona intestinalis exposed to tributyltin (TBT) at 10-5 M using the histochemical method of Karnovsky and Roots. Relative to vertebrate tissues and organs, the development of adult form of ascidians is interesting, because the analysis of many nuclear genes indicated that the ascidians are the closest living relatives of the vertebrates. Therefore, toxicity research using different approaches could provide data for comparative studies with vertebrates. AChE is over-expressed under chemical stress and in some diseases of vertebrates. Therefore, AChE is considered a biomarker of environmental co…
Parasite-induced aggression and impaired contest ability in a fish host
2010
Abstract Background Success of trophically transmitted parasites depends to a great extent on their ability to manipulate their intermediate hosts in a way that makes them easier prey for target hosts. Parasite-induced behavioural changes are the most spectacular and diverse examples of manipulation. Most of the studies have been focused on individual behaviour of hosts including fish. We suggest that agonistic interactions and territoriality in fish hosts may affect their vulnerability to predators and thus the transmission efficiency of trophically transmitted parasites. The parasite Diplostomum spathaceum (Trematoda) and juvenile rainbow trout, Oncorhynchus mykiss, were used to study whe…
Development and validation of a bioenergetics model for juvenile and adult burbot
2003
Oxygen consumption of juvenile and adult burbot Lota Iota was measured in an intermittent-flow respirometer to determine the effect of temperature and fish body mass on metabolic rate. These results were combined with data from earlier experiments and the 'Wisconsin bioenergetics' model was constructed. The model was validated under laboratory conditions by comparing observed and predicted food consumption and growth of burbot fed on dead vendace Coregonus albula. There was a good correspondence between observed and estimated growth and food consumption under experimental conditions: the mean absolute per cent errors of growth and food consumption were 4.8 and 24.0%. Estimated values with t…
Life in the ice lane: the winter ecology of stream salmonids
2007
Despite the common view that conditions in winter strongly influence survival and population size of fish, the ecology of salmonids has not been as extensively studied in winter as in other seasons. In this paper, we review the latest studies on salmonid winter survival, habitat use, movement and biotic interactions as they relate to the prevailing physical and habitat conditions in rivers and streams. The majority of research conducted on the winter ecology of salmonids has been carried out in small rivers and streams, where temperatures are above zero and where there is no ice. Investigations in large rivers, regulated and dredged rivers, and under conditions of different ice formations a…
Development and habitat selection of a new sanguinicolid parasite of cultured greater amberjack, Seriola dumerili, in the Mediterranean
2009
Abstract This study presents a description of the developmental stages of a new sanguinicolid disease agent (Paradeontacylix ibericus) of cultured Seriola dumerili (greater amberjack) in the Mediterranean, and investigates parasite habitat selection in the definitive host and the development of sanguinicolidosis in experimental, inshore cultures of S. dumerili . Two experimental surveys were carried out using fish captured as wild 0+ juveniles in the aquaculture facilities at Puerto de Mazarron (Spain). Encysted, early post-cercarial stages (schistosomula) were detected in histological sections of the pelvic and thoracic muscles of fish and four subsequent stages of parasite development wer…
Feeding ecology of the loggerhead turtle Caretta caretta in the western Mediterranean
2001
We studied the feeding ecology of juvenile loggerhead turtles Caretta caretta in the western Mediterranean based on the contents of the digestive tract of 54 turtles (range of CCL: 34–69 cm) seized in Barcelona (Spain) in 1991. Turtles had been captured in fishing trawls, but specific information about dates and localities is not available. Despite this limitation, we obtained interesting evidences about the foraging strategies of loggerheads, with potentially important conservation implications. We report 33 new taxa in the diet. Results indicated that western Mediterranean loggerheads feed in an opportunistic way. Numerically, fish made up the most important prey group, followed by pelagi…
Die Diagnose der mitteleuropäischen Urodela (Amphibia) nach der Morphologie des Mundhöhlendaches
1980
AbstractThe pattern of teethrows on the roof of the mouth and the numbers of teeth enable as diagnostic characteristics the determination of the Central European Urodela. Particularly the distinction between T. vulgaris and T. helveticus is now definite in all stages after metamorphose. The degree of development of the vomeromaxillarfold (Triturus) respectively of the vomerfold (Salamandra) indicates whether a specimen is an adult, juvenile or newly metamorphosed one.
Plant regeneration from juvenile and adult Anthyllis cytisoides, a multipurpose leguminous shrub
1997
Summary Anthyllis cytisoides , a legume shrub used for afforestation and reclamation of degraded Mediterranean areas, was successfully micropropagated from expiants of juvenile (cotyledonary nodes and apical buds) and adult origin (axillary buds). Multiple shoot formation was dependent on the presence of benzyladenine in the induction medium. Of the salt formulation and expiants examined, the higher proliferation rates were obtained when axillary buds from adult plants were cultured on a modified Schenk and Hildebrandt medium. Following the preferred protocol, shoot yield reached values greater than 100 shoots per expiant. Plants were easily rooted and transplanted into greenhouse.
The effect of the length of repeated feed deprivation between single meals on compensatory growth of pikeperch Sander lucioperca
2009
Abstract Juvenile pikeperch ( Sander lucioperca ) were reared for 58 days according to one of the following feeding regimes: control (fed once every day); 1 + 1 (fed every other day); 1 + 3 (one-day feeding followed by a three-day feed deprivation); and 1 + 6 (fed once a week). Control fish had significantly higher growth rate than the 1 + 3 and 1 + 6 fish, and consequently the final weight of the controls (125.2 ± SD 30.0 g, n = 4) was higher than that of the 1 + 3 (84.0 ± 17.9 g) and 1 + 6 fish (64.7 ± 7.2 g). Fish in the treatment groups were capable to compensate for the reduced number of feedings by increasing intake relative to the controls when feed was available. This hyperphagic r…