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  • 1995-1999  (479)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 36 (1997), S. 299-302 
    ISSN: 1436-6215
    Schlagwort(e): Energy retention ; protein retention ; fat retention ; growth ; body composition ; broilers ; Energieansatz ; Proteinansatz ; Fettansatz ; Wachstum ; Körperzusammensetzung ; Broiler
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Mit steigender Aufnahme erhöht sich der Körperfettgehalt und der Körperproteingehalt nimmt ab. Es wird oft angenommen, daß jede Zunahme im Ansatz mit mehr Fett und weniger Protein verbunden ist. Experimentelle Ergebnisse widerlegen jedoch diese Annahme. In zwei Experimenten mit männlichen Broilerhühnern wurden die Tiere auf einem Niveau von 60 % und 100 % der empfohlenen Energieaufnahme gefüttert. Die Körperzusammensetzung bei 1500 g zeigte, wie erwartet, daß sich bei steigenden Aufnahmen der Körperfettgchalt vergrößert und der Körperproteingehalt abnimmt. Fettund Proteinansatz waren linear mit der totalen Energieretention (ER) korreliert. Das bedeutet, daß jede Zunahme im Ansatz den gleichen Protein- und Fettgehalt besitzt. Wenn der Fettansatz gleich Null ist wird nur Protein, etwa 50 % des maximalen Ansatzes, retiniert. Wenn ER=O ist, wird Protein angesetzt und Fett mobilisiert. Energie-und N-Bilanzuntersuchungen bestätigen die konstante Zusammensetzung jeder Vergrößerung des Ansatzes. Die Ergebnisse beider Experimente zeigen, daß die ER aus zwei Komponenten besteht: einem basalen konstanten täglichen Proteinansatz und einer variablen zusätzlichen ER, die hauptsächlich aus Fett besteht. Der basale Proteinansatz beträgt etwa 50 % des maximalen Ansatzes. Mit steigenden Energieaufnahmen wird der basale Proteinansatz mit einer zusätzlichen Menge von Protein und Fett im konstanten Verhältnis ergänzt.
    Notizen: Summary With increasing intakes the body fat content increases and that of protein decreases. It is most often assumed that this is brought about because each increment in retention contains more fat and less protein. Experimental results, however, showed that this explanation is not true. In two experiments male broiler chickens were fed at levels between 60 and 100 % of recommended energy intake. Body composition at 1500 g showed, as expected, that with increasing intakes body fat content increased and protein content decreased. Both fat and protein retention per day were linearly related to total energy retention (ER). This means that each increment in retention has the same protein and fat content. At zero fat retention only protein was retained, about 50 % of maximal retention. At zero ER protein was retained and fat mobilized. Energy and N balance experiments confirmed the constant composition of each increment in retention. The results of both experiments show that total ER consisted of two components: a basic constant daily protein retention and a variable additional ER, mainly consisting of fat. The basic protein retention is about half of maximal retention. With increasing energy intakes the basic protein retention is combined with an additional amount of protein and fat in a constant ratio.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 36 (1997), S. 332-335 
    ISSN: 1436-6215
    Schlagwort(e): Nutrient intake ; protein metabolism ; protein synthesis ; growth ; energy expenditures ; Nährstoffaufnahme ; Proteinstoffwechsel ; Proteinsynthese ; Wachstum ; Energieaufwand
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eine Zunahme von fettfreiem Gewebe tritt auf, wenn die Proteinsynthese größer ist als der Proteinabbau. Obwohl während des Wachstums von der Geburt bis zur Reife die absoluten Proteinsynthese- und -abbauraten ansteigen, nehmen dagegen die fraktionellen Raten ab. Bcide Prozesse reagieren auf die Nährstoffaufnahme. Es gibt aber deutliche Unterschiede zwischen den verschiedenen Geweben. Protein, Kohlenhydrate und Fett können den Proteinansatz bei unreifen Tieren und Kindern stimulieren. Die zugrundeliegenden Mechanismen und die Energieaufwendungen scheinen jedoch unterschiedlich zu sein.
    Notizen: Summary Lean tissue growth occurs when the rate of protein synthesis exceeds the rate of protein breakdown. Althoughabsolute rates of protein synthesis and breakdown rise during growth from birth to maturityfractional rates fall. Both these processes are sensitive to nutrient intake but responses to feeding vary greatly amongst different tissues. Protein, carbohydrate and fat can all stimulate body protein accretion in immature animals and in children but the mechanisms by which they do so, and the energy expenditures involved, seem to be different.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Empirical economics 24 (1999), S. 23-44 
    ISSN: 1435-8921
    Schlagwort(e): Key words: Cointegration ; convergence ; growth ; Kalman filter ; JEL classifications: C22 ; O47 ; O57
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Wirtschaftswissenschaften
    Notizen: Abstract. Augmented Dickey Fuller (ADF) and Kalman filter convergence tests are applied to annual GDPs per head to 16 industrialised countries from 1890 to 1989. Results favour convergence towards the US with a structural break following the Second World War. Estimates suggest that steady-states were higher after the war and that speeds of convergence are different across countries. The Kalman filter method dismissed the no convergence hypothesis more often than its ADF counterpart. This could explain the apparent contradiction in earlier empirical work on similar data sets (cross-section methods tended to favour convergence while time series methods were unable to dismiss the no convergence hypothesis.)
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 141-144 
    ISSN: 1570-7458
    Schlagwort(e): Polygonia c-album ; Nymphalidae ; host-plant selection ; growth ; size
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1570-7458
    Schlagwort(e): amylase inhibitor ; red kidney bean ; hard red winter wheat ; growth ; insects ; beetles ; plant resistance ; stored products ; protease inhibitor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Insect α-amylase inhibiting and/or growth inhibiting activities of proteinaceous inhibitors from red kidney bean (Phaseolus vulgaris) and hard red winter wheat (Triticum aestivum) were examined. The bean inhibitor was most effectivein vitro against α-amylases from the red flour beetle (Tribolium castaneum) and the confused flour beetle (T. confusum), followed by those from the rice weevil (Sitophilus oryzae) and yellow mealworm (Tenebrio molitor). The insect enzymes were from two- to 50-fold more susceptible than human salivary α-amylase. When the inhibitors were added at a 1% level to a wheat flour plus germ diet, the growth of red flour beetle larvae was slowed relative to that of the control group of larvae, with the bean inhibitor being more effective than the wheat inhibitor. Development of both the red flour beetle and flat grain beetle (Cryptolestes pusillus) was delayed by 1% bean inhibitor, but development of the sawtoothed grain beetle (Oryzaephilus surinamensis) and lesser grain borer (Rhyzopertha dominica) was not affected by either the bean or wheat inhibitor at the 1% level. Rice weevil adults fed a diet containing 1% bean or wheat inhibitor exhibited more mortality than weevils fed the control diet. When the wheat amylase inhibitor was combined with a cysteine protease inhibitor, E-64, and fed to red flour beetle larvae, a reduction in the growth rate and an increase in the time required for adult eclosion occurred relative to larvae fed either of the inhibitors separately. The bean inhibitor was just as effective alone as when it was combined with the protease inhibitor. These results demonstrate that plant inhibitors of insect digestive enzymes act as growth inhibitors of insects and possibly as plant defense proteins, and open the way to the use of the genes of these inhibitors for genetically improving the resistance of cereals to storage pests.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 79 (1996), S. 335-344 
    ISSN: 1570-7458
    Schlagwort(e): alkaloid ; developmental time ; early instars ; growth ; Manduca sexta ; molting duration ; phenolics ; plant-herbivore interactions ; thermal regime
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To understand the mechanisms underlying plant-insect herbivore interactions, it is necessary to examine the simultaneous effects of temperature, food quality and larval age. We examined the simultaneous effects of three allelochemicals (tomatine, rutin and chlorogenic acid) on the performance of first and second instar Manduca sexta larvae under two representative thermal regimes 21 : 10°C and 26 : 15°C for spring and summer, respectively. Thermal regime and allelochemicals interacted to influence the time from egg hatch to ecdysis to the third instar. On average, it took about half as much time to reach the third instar at 26 : 15°C as it did at 21 : 10°C. Separately, tomatine and rutin had a negative effect on developmental time from egg hatch to the third instar, but their simutaneous effects were not additive. Chlorogenic acid significantly reduced the negative effect of tomatine. The magnitude of the allelochemical effect was larger at the cooler thermal regime compared to the warmer regime. For instance, chlorogenic acid by itself had no effect at the 26 : 15°C regime, but at the 21 : 10°C regime it significantly shortened total developmental time. The effect of chlorogenic acid on stadium duration was distinctly different for the two instars. Chlorogenic acid shortened stadium duration of first instar larvae. However, depending on thermal regime and the presence of tomatine, chlorogenic acid had a negative, positive or neutral effect on stadium duration of second instar larvae. Molting duration of second instar larvae was shortened by a half day at the warmer thermal regime but was not affected by the allelochemicals. Final larval weight was influenced by rutin and chlorogenic acid. Caterpillars fed diets containing 20 μmoles of rutin were on average 10% lighter than those fed plain diet, whereas those fed diets containing 20 μmoles of chlorogenic adic were on average 7% heavier. However, the effect of chlorogenic acid depended on thermal regime. Overall, our results indicated that: 1) temperature and food quality can interact to influence insect performance and 2) these effects are influenced by larval age.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 443-451 
    ISSN: 1570-7458
    Schlagwort(e): beta-carboline alkaloid ; Trichoplusia ni ; harmane ; harmaline ; amitriptyline ; imipramine ; monoamine oxidase inhibitor ; tricyclics ; growth ; feeding behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this study we investigated the effects of two naturally occurring beta-carboline alkaloids and two synthetic tricyclic antidepressants on the growth and food consumption of fifth instar larvae of the cabbage looper, Trichoplusia ni Hübner (Lepidoptera: Noctuidae). In artificial diets at high concentrations (3,000 ppm), harmane, amitriptyline, and imipramine reduce growth and feeding; harmane reduced feeding consistently at a lower concentration (200 ppm). In animals other than insects, beta-carboline alkaloids inhibit monoamine oxidase (MAO) activity and thus affect rates of disposition of serotonin and other monoamine neurotransmitters. Because brain serotonin levels are associated with variation in rates of carbohydrate and protein intake in insects, the effects of beta-carboline alkaloid ingestion on dietary self-selection behavior were examined. Choosing between diets lacking carbohydrate but containing protein and diets lacking protein but containing carbohydrate, larvae consumed a greater proportion of diet containing protein but lacking carbohydrate in the presence of harmane than in its absence. These results are consistent with beta-carboline alkaloid-mediated persistence of serotonin in the brain due to MAO inhibition. Alternatively, these results could reflect alkaloid-mediated peripheral inhibition of sucrose taste receptors influencing ingestive behaviors. That beta-carboline alkaloid ingestion is associated with changes in feeding behavior is consistent with a possible defensive role for these compounds in plant foliage.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    ISSN: 1570-7458
    Schlagwort(e): insect endocrinology ; ecdysone ; juvenile hormone ; reproduction ; growth ; inhibin ; oostatin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The first insect folliculostatic peptide was isolated from vitellogenic ovaries of the mosquitoAedes aegypti. This decapeptide directly inhibits trypsin biosynthesis in the gut, and indirectly ovarian development. The factor was named Trypsin Modulating Oostatic Factor or TMOF by its discoverers. From the fleshfly Neobellieria bullata 2 folliculostatins have been isolated, the hexapeptide Neb-TMOF and the 19-mer Neb-colloostatin. The available data suggest that at least 2 of the 3 folliculostatins originate from matrix (like) proteins present in the ovary, a hitherto unknown source of hormones. Furthermore, one of the folliculostatins (Neb-TMOF) is a potent inhibitor of ecdysone biosynthesis by larval ring glands of fleshflies. The discovery of the dipteran folliculostatins, which do not show any resemblance to inhibins of vertebrates, may significantly contribute to a better understanding of the hormonal control of growth in insects and perhaps, in other animals as well. None of the 3 folliculostatins is blocked at its N- or C-terminus. This, in combination with the pleiotropy of their effects and the narrow species specificity make such peptides prime candidates for, testing their potential in insect pest control by means of molecular biological methods.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 51 (1995), S. 768-774 
    ISSN: 1420-9071
    Schlagwort(e): Cortisol ; stress ; heat ; Antarctic ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Radioimmunoassay was used to determine levels of the stress-inducible glucocorticoid, cortisol, circulating in the plasma of the extremely stenothermal Antarctic fishPagothenia borchgrevinki at rest and after heat stress. Fish sampled immediately after capture (−1.9°C) had low cortisol levels (10.4±1.4 ng ml−1, mean±SEM) as did fish which were laboratory rested for 3 days. Sudden exposure to 5°C (48h) resulted in a peak cortisol value after 3 h (69.9±6.8 ng ml−1) whereas exposure to 8°C (6h) resulted in a peak value after 1 h (73.5±8.0 ng ml−1). At both temperatures levels remained significantly elevated (p〈0.05) for the entire period of exposure. Increased temperature also resulted in a significant change in haemoglobin, haematocrit and mean cell haemoglobin concentration (MCHC) (p〈0.05). Plasma lactate was significantly elevated only after exposure to 8°C (p〈0.05). Plasma cortisol levels fromP. borchgrevinki are reported here for the first time and show this cryopelagic Antarctic species to have an unusual hormonal stress profile.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    ISSN: 1432-0975
    Schlagwort(e): Key words Dispersal ; coral reefs ; fish ; swimming ; Larvae ; Juveniles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie
    Notizen: Abstract  Characteristics of the pelagic stages of reef fishes have generally been investigated at the family level, which may mask important differences among species. Here the variation in sustained swimming ability of the late pelagic stages is examined among species, within two families (Pomacentridae and Chaetodontidae). The pomacentrids displayed a 7.5-fold difference in sustained swimming ability across 24 species, while the chaetodontids displayed a 2-fold difference across 10 species. The variation within the Pomacentridae was not related to pelagic larval duration, post-settlement habitat or taxonomy. There was, however, a significant correlation between sustained swimming ability and total length (TL) of individuals (r=0.435, P〈0.0001). Differences in the mean distance swum by pomacentrid species, however, was most strongly related to differences in mean wet weight (r=0.814, P〈0.0001). When the mean distance swum by species was scaled with respect to mean TL there was still a strong correlation with mean wet weight (r=0.644, P〈0.005). Among chaetodontid individuals TL and sustained swimming ability were not correlated (r=−0.004, P=0.978). Furthermore, sustained swimming ability was not significantly related to the trans-oceanic distribution of species in either family. The variation in sustained swimming ability, however, may contribute to explanations of the observed levels of gene flow within populations.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    European journal of nutrition 36 (1997), S. 205-213 
    ISSN: 1436-6215
    Schlagwort(e): Frying ; growth ; liver lipids ; lipaemia ; olive oil ; pregnancy ; rat ; Fritierung ; Wachstum ; Leberfett ; Olivenöl ; Schwangerschaft ; Ratte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Um Informartionen über den Zusammenhang zwischen der Aufnahme von Fett, das zum Fritieren benutzt wurde, und dem Fetthaushalt während Perioden starken Körperaufbaus zu haben, wurde der Einfluß der Aufnahme von frischem Olivenöl (Gehalt polarer Verbindungen, 2 %; Ölsäure 78,9 mg/100 mg Öl, und Linolsäure 7 mg/100 mg Öl) und von Olivenöl, das 15 mal in Folge für das Fritieren von Kartoffeln benutzt worden war (Gehalt polarer Verbindungen 9 %; Ölsäure 75,8 mg/100mg Öl und Linolsäure 6,2 mg/100mg Öl) während der Gravidität, untersucht. Dazu wurden trächtige Wistar Ratten in zwei Gruppen geteilt, die beide eine isokalorische Diät bekamen, deren Fettanteil 15 % von frischem (unbenutztem) (P1) bzw. fritiertem (benutztem) (P2) Olivenöl stammte mit nicht trächtigen Ratten verglichen. Die Gravidität erhöhte (p〈0,01) die Futteraufnahme, das Körpergewicht, die Gewichtszunahmen und die Futterverwertung. Die Ölqualität beeinflußte dagegen diese Parameter nicht. Während der Gravidität stiegen die Serumwerte der Triglyceride (TG) (p〈0,01) und des Cholesterins (TC) (p〈0,05) an, während die der Phosphatide (PH) sanken (p〈0,01). Ein signifikanter Effekt der Ölqualität und eine Wechselwirkung zwischen Gravidität und Öl wurde für TG und PH festgestellt. Das Gewicht und der Fettgehalt der Leber der trächtigen Ratten stiegen signifikant an (p.〈0.05), Leber TC, TG und PH stiegen während der Gravidität (ungefähr um das 3-fache der Ausgangswerte), aber es traten keine signifikanten Unterschiede zwischen der Aufnahme von benutztem und nicht benutztem Öl (P2 vs P1) auf. Die Ergebnisse zeigen, daß die Aufnahme von leicht verdorbenem Olivenöl als alleinige Fettquelle der Nahrung keine besonderen Folgen für die Gravidität hat, was die Gewichtszunahme der Mütter und der Feten, die Lipämie und die Zusammensetzung des Leberfetts betrifft.
    Notizen: Summary The effect of the consumption of unused olive oil (polar content, 2 %; oleic acid, 78.9 mg/100 mg oil, and linoleic acid 7 mg/100 mg oil) and olive oil used discontinuously for frying potatoes 15 times (polar content, 9 %; oleic acid, 75.8 mg/100 mg oil and linoleic acid 6.2 mg/100 mg oil) was studied in pregnant rats with the aim of better understanding the relationship between the consumption of fat used in frying and lipid metabolism during periods of intense anabolism. Trials were performed in pregnant Wistar rats, divided into 2 groups and fed isocaloric diets in which the fat content (15 % wt/wt) consisted of unused olive oil (P1) or oil previously used for frying (P2), and the results were compared with those of nonpregnant rats fed unused olive oil (NP1) and olive oil used for frying (NP2). Pregnancy increased (p〈0.01) food intake, body weight, weight gain, and food efficiency ratio (P2 vs NP2 and P1 vs NP1, respectively), but the treatment of oil included in the diets did not alter these parameters. Gestation significantly increased the serum triglyceride (TG) (p〈0.01) and total cholesterol (TC) (p〈0.05) concentrations and diminished that of phospholipids (PH) (p〈0.01). A significant effect of the type of oil consumed and a pregnancy x oil interaction on Tg and PH levels was observed. The weight of the liver and its fat content increased significantly (p〈0.05) as a result of pregnancy. Liver TC, TG, and PH increased (approximately 3 times the original values) during gestation, but no significant differences due to the intake of used or unused oil (P2 vs P1) were observed. The results indicate that the consumption of moderately altered olive oil, as the sole source of fat, does not alter the effect of pregnancy on the mothers' weight gain, lipaemia, and hepatic fat composition to any important degree.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    ISSN: 1436-6215
    Schlagwort(e): Body composition ; fat ; growth ; somatotropin ; pig ; Körperzusammensetzung ; Fett ; Wachstum ; Somatotropin -Schwein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An 78 männlichen Kastraten und weiblichen Schweinen der Kreuzung Pietrain x (Deutsches Edelschwein x Deutsche Landrasse) wurden Untersuchungen zum Einfluß einer porcinen Somatotropin (pST)-Behandlung während des Wachstums auf die chemische Körperzusammensetzung der Tiere, das Adipozyten-Wachstum und das Fettsäure-Profil des Rückenspecks untersucht. Die intramuskulären Injektionen (1 oder 3 mg pST) wurden täglich ab durchschnittlich 65 kg Lebendgewicht bis zum Schlachten verabreicht. Nach der pST-Behandlung wurden bei den Kastraten in allen untersuchten Merkmalen signifikante Unterschiede festgestellt, während sich bei den weiblichen Tieren nur leichte Reaktionen zeigten. Das pST verursachte eine Zunahme des Wasserund Proteingehaltes bei gleichzeitiger Reduzierung des Lipidgehaltes besonders in den fettreichen Körperteilen der Tiere. Im Rückenspeck war der Gehalt an ungesättigten Fettsäuren erhöht und der Fettzelldurchmesser erniedrigt.
    Notizen: Summary Seventy eight growing-finishing pigs (male castrates and females) of the cross-breed Pietrain x (Large White x German Landrace) were used to investigate the effects of pST treatment on the chemical composition of the body, the growth of adipocytes, and the fatty acid profile of the backfat. Intramuscular injections (1 or 3 mg pST) were administered daily from an average weight of 65 kg up to slaughter. After pST treatment significant changes in all studied characteristics were observed in barrows, whereas the females exhibited very small responses. The pST caused an increase of water and protein contents and a simultaneous decrease of lipid content especially in body parts rich in fat. Furthermore, the proportion of unsaturated fatty acids increased and the fat cell diameter decreased in the backfat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Microchimica acta 119 (1995), S. 305-310 
    ISSN: 1436-5073
    Schlagwort(e): mercury ; fish ; collaborative study ; atomic absorption spectrometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract One of the major analytical problem in the analysis of fish tissues for total mercury is the dissolution of the sample. This paper compares two different methods of wet digestion (microwave and closed pressurized vessel), followed by FIAAS as final determination and a Zeeman-solid-sample-AAS determination method without previous mineralization. Six fish samples were selected for this study. The top, the central and the bottom portions of the fish were analyzed separately. The mercury contents in the bottom portions determined by Zeeman-solid-sample-AAS were significantly higher than those obtained by the other two systems. A good correlation was observed among the results of the different techniques.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    ISSN: 1436-5073
    Schlagwort(e): microwave digestion ; fish ; mercury ; CVAAS
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Food samples digestion, in view to quantify total mercury, is the first step to perform before measuring mercury by cold vapour atomic absorption spectrometry (CVAAS). We have compared two microwave digestion systems, one working at atmospheric pressure (open system) and the other one under pressure (closed system). Results obtained for fish muscle samples by the two methods are in good agreement. However, fat is not digested in the open system, whereas in the closed system no more fat remains in the final solution. During the quantification step, applying the CVAAS technique, we have noticed that the choice and the concentration of the reductant solution is very important to obtain good results. Elaborated methods have been validated using certified reference materials.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Journal of productivity analysis 8 (1997), S. 293-310 
    ISSN: 1573-0441
    Schlagwort(e): growth ; USagriculture ; externalities ; spill-overs ; public R and D
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Wirtschaftswissenschaften
    Notizen: Abstract Growth in U.S. agriculture is linked to the non-farm economy through domestic terms of trade and factor market adjustments. With almost stable input growth, the relatively large contributions from growth in Total Factor Productivity (TFP) are passed on to intermediate and final consumers in the form of declining real prices for primary farm products. The resulting net growth in the real value of farm output (GDP) is relatively low (0.25% per annum). The decomposition of TFP suggests that public agricultural stock of knowledge and infrastructure are “robustly” associated with TFP growth, while spill-overs from private agricultural and economy wide research and development (R and D) are positive but, relatively small.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    ISSN: 1572-977X
    Schlagwort(e): culverts ; culvert trap ; mosquito impoundment ; seine ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Fish population dynamics in a 24.3 ha mangrove-dominated mosquito impoundment in east-central Florida were examined by seining and culvert traps before and after installation of culverts that established estuarine connection for the first time in 39 years. In a 27-day period following the culvert opening, fish species increased from 9 to 21, while total number of fish in the impoundment decreased. Movement of fishes through culverts in both directions commenced immediately following culvert opening. Recruitment of transient species into the impoundment appeared to key on a single wind-driven high tide event. Such short-term events may be important cues for fish movement into and out of impounded salt marshes.
    Materialart: Digitale Medien
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  • 17
    ISSN: 1572-977X
    Schlagwort(e): Avicennia alba ; growth ; internodal sequences ; mangrove age determination ; Rhizophora apiculata ; Sonneratia caseolaris ; Thailand
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The occurrence of periodic changes in the length of the internodes of the seedlings of SE Asian mangrove species (Rhizophora apiculata, Avicennia alba, and Sonneratia caseolaris) growing in the Pak Phanang estuary (Nakhon Si Thammarat, SE Thailand) was confirmed. The annual nature of these periodic changes was verified through comparisons with the observed average number of internodes produced by plants tagged for one year. The cycles in the sequence of internodal length of the seedlings had an average (± SE) period of 16.0 ± 0.78 internodes for Avicennia alba, 25.0 ± 1.2 internodes for Sonneratia caseolaris, and 8.29 ± 0.40 internodes for Rhizophora apiculata. These values are remarkably close to, and not significantly different (t‐test, P 〉 0.05) from the average (± SE) annual number of internodes of 17.6 ± 0.8 for Avicennia alba, 28.8 ± 2.1 for Sonneratia caseolaris, and 8.03 ± 0.36 for Rhizophora apiculata produced in a year by tagged plants. In addition, the average (± SE) growth of the tagged plants was 0.39 ± 0.018 cm day-1 for Avicennia alba, 0.24 ± 0.015 cm day-1 for Sonneratia caseolaris, and 0.091 ± 0.0036 cm day-1 for Rhizophora apiculata. These estimates were very close to those (0.45 ± 0.06 cm day-1 for Avicennia alba, 0.32 ± 0.01 cm day-1 for Sonneratia caseolaris, and 0.13 ± 0.005 cm day-1 for Rhizophora apiculata) derived as the product of the mean number of internodes produced per day, calculated from the inferred number of internodes produced per year, and the mean length of the internodes of the plants. These findings indicate that the use of regular, annual changes in the length of the internodes of mangrove seedlings can be used reliably to determine their age and to estimate their growth rate.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    ISSN: 1420-9055
    Schlagwort(e): Phoxinus phoxinus ; fish ; Diplostomum phoxini ; Macrolecithus papilliger ; parasitism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The influence of parasites on the breeding biology of the European minnow (Phoxinus phoxinus) was studied by examining 268 adult and 59 young-of-the-year minnows from an artificial Swiss Alpine lake for parasites during the breeding seasons in 1990 and 1991. Two trematode parasites;Diplostomum phoxini, in their brains, andMacrolecithus papilliger, in their guts, were found. The prevalence ofD. phoxini was 100% in both years. The mean abundance was 231 in 1990 and 448 in 1991; the difference was significant. Prevalence (and abundance) ofM. papilliger was 37.5% (1.04±0.39) in 1990 and 59.5% (2.68±0.55) in 1991; also significantly higher in 1991 than in 1990. No differences in prevalence or abundance between males and females were found. Numbers of both parasites were significantly correlated with fish length. There was seasonal variation in the abundance ofD. phoxini metacercariae, with a peak in June/July in both years. The prevalence ofM. papiller decreased after July in both years. Distribution of the two trematodes was overdispersed as indicated by the variance to mean (abundance) ratio. The observed seasonal variation inD. phoxini abundance also suggests that sublethal parasites could influence the population dynamics of their hosts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Aquatic sciences 57 (1995), S. 106-118 
    ISSN: 1420-9055
    Schlagwort(e): Benthos ; fish ; vertical distribution ; predation risk ; selective fishing ; Lake Constance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To compare the vertical distributions of benthos and fish species of Upper Lake Constance (Bodensee), 552 benthos samples were taken with an Auerbach grab at four transects (10–250 m). An additional 54 samples (1–10 m) were collected elsewhere. Complementary data was taken from the literature. In winter, most fish feed on benthos, mainly chironomids, but in summer less than 5% do so. Formerly the bottom gill-netting aimed mainly at catchingCoregonus pidschian, but it now aims atPerca fluviatilis. Contrary to expectation, in winter the greatest abundance ofP. fluviatilis is much deeper (55 m) than that of its preferred food, i.e. chironomids (〈20 m). Comparably,C. pidschian also stayed deeper than its main food source (chironomids and mollusks).Lota lota, Salvelinus profundus andS. alpinus — unlike the unwanted cyprinids — also stay or stayed deeper than the attractive chironomids. It is argued that the fish reduce their “predation risk”, i.e. the risk of being gillnetted in the upper 50 m, by “selecting” the deeper less dangerous, but also less food-abundant habitat. Balancing predation risk against food abundance may have led to “survival of the deepest”.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 51 (1995), S. 284-288 
    ISSN: 1420-9071
    Schlagwort(e): Alternating high magnetic fields ; eddy current ; magnetic flux concentration ; Caenorhabditis elegans ; growth ; reproduction ; behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Here we describe a device for testing possible influences of high magnetic fields on biological processes, by which alternating-current magnetic stimuli as high as 1.7 T can be administered. Experiments with a simple multicellular organism, the nematodeCaenorhabditis elegans, revealed that intermittent exposure to the magnetic fields modestly inhibited the animal's reproduction as well as its post-embryonic development, and caused a marked but transient derangement in its locomotory behavior. Available evidence indicates that alternating high magnetic fields can elicit both chronic and acute biological effects, but that the effects may be well tolerated or compensated for by the living organism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    ISSN: 1432-1939
    Schlagwort(e): Key words Agrostis canina ; CO2 vents ; photosynthesis ; lignification ; growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The aim of this study was to characterise growth and photosynthetic capacity in plants adapted to long-term contrasting atmospheric CO2 concentrations (C a). Seeds of Agrostis canina L. ssp. monteluccii were collected from a natural CO2 transect in central-western Italy and plants grown in controlled environment chambers at both ambient and elevated CO2 (350 and 700 μmol mol−1) in nutrient-rich soil. Seasonal mean C a at the source of the plant material ranged from 610 to 451 μmol CO2 mol−1, derived from C4 leaf stable carbon isotope discrimination (δ13C). Under chamber conditions, CO2 enrichment stimulated the growth of all populations. However, plants originating from elevated C a exhibited higher initial relative growth rates (RGRs) irrespective of chamber CO2 concentrations and a positive relationship was found between RGR and C a at the seed source. Seed weight was positively correlated with C a, but differences in seed weight were found to explain no more than 34% of the variation in RGRs at elevated CO2. Longer-term experiments (over 98 days) on two populations originating from the extremes of the transect (451 and 610 μmol CO2 mol−1) indicated that differences in growth between populations were maintained when plants were grown at both 350 and 700 μmol CO2 mol−1. Analysis of leaf material revealed an increase in the cell wall fraction (CWF) in plants grown at elevated CO2, with plants originating from high C a exhibiting constitutively lower levels but a variable response in terms of the degree of lignification. In vivo gas exchange measurements revealed no significant differences in light and CO2 saturated rates of photosynthesis and carboxylation efficiency between populations or with CO2 treatment. Moreover, SDS-PAGE/ LISA quantification of leaf ribulose bisphosphate carboxylase/oxygenase (Rubisco) showed no difference in Rubisco content between populations or CO2 treatments. These findings suggest that long-term adaptation to growth at elevated CO2 may be associated with a potential for increased growth, but this does not appear to be linked with differences in the intrinsic capacity for photosynthesis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Journal of population economics 9 (1996), S. 415-428 
    ISSN: 1432-1475
    Schlagwort(e): H42 ; J 13 ; O 11 ; Fertility ; growth ; public education and health
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Sociologie , Wirtschaftswissenschaften
    Notizen: Abstract This paper considers the implications of the financing of government services to children when fertility decisions are endogenously determined. In particular, it is shown that when the services are financed by taxation, the equilibrium outcome is biased away from the socially preferred result. The bias results in higher fertility rates and lower economic growth rates than the efficient social optimum. This arises because each household internalizes the benefits, but not the costs of the tax-financed services. We consider alternative methods of financing the public provision of services and find that a combination of taxation and vouchers can eliminate the bias in the equilibrium outcome.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Journal of population economics 11 (1998), S. 273-291 
    ISSN: 1432-1475
    Schlagwort(e): JEL classification: F22 ; O3 ; J61 ; Key words: Immigration ; assimilation ; growth ; diversity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Sociologie , Wirtschaftswissenschaften
    Notizen: Abstract. This paper analyzes the welfare effects of immigration and its subsequent effect on ethnic diversity in a model featuring human capital spillovers which depend on the degree of ethnic heterogeneity, variation rates of time preference across individuals and endogenous levels of immigration and assimilation. In the model, an increase in ethnic diversity reduces the spillovers effect for the majority. Nonetheless, immigration can be welfare improving for the majority ethnic group even if it increases the degree of diversity as long as it raises the average human capital level and/or growth rate by increasing the proportion of people with low rates of time preference. However, if an economy is too homogenous, it will not be able to attract immigrants. Finally, if the level of immigration is not too high, then immigration also raises the net benefits to assimilation which leads to a more homogenous economy.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Journal of population economics 11 (1998), S. 517-534 
    ISSN: 1432-1475
    Schlagwort(e): Key words: Fertility ; mortality ; growth ; JEL classification: J13 ; O41
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Sociologie , Wirtschaftswissenschaften
    Notizen: Abstract. Economic and demographic outcomes are determined jointly in a choice-theoretic model of fertility, mortality and capital accumulation. There is an endogenous population of reproductive agents who belong to dynastic families of overlapping generations connected through altruism. In addition to choosing savings and births, parents may reduce (infant) deaths by incurring expenditures on health-care which is also provided by the government. A generalised production technology accounts for long-run endogenous growth with short-run transitional dynamics. The analysis yields testable time series and cross-section implications which accord with the empirical evidence on the relationship between demography and development.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Journal of population economics 9 (1996), S. 415-428 
    ISSN: 1432-1475
    Schlagwort(e): Key words: Fertility ; growth ; public education and health
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Sociologie , Wirtschaftswissenschaften
    Notizen: Abstract. This paper considers the implications of the financing of government services to children when fertility decisions are endogenously determined. In particular, it is shown that when the services are financed by taxation, the equilibrium outcome is biased away from the socially preferred result. The bias results in higher fertility rates and lower economic growth rates than the efficient social optimum. This arises because each household internalizes the benefits, but not the costs of the tax-financed services. We consider alternative methods of financing the public provision of services and find that a combination of taxation and vouchers can eliminate the bias in the equilibrium outcome. JEL classification: H42, J13, O11
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    ISSN: 1432-072X
    Schlagwort(e): Key words Protein phosphorylation ; ATP-Pi exchange ; Light-harvesting complexes ; Reaction center ; Photosynthesis ; Photomorphogenesis ; Membrane ; growth ; Polypeptide insertion ; Phospho-amino esters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Membranes of Rhodobacter capsulatus strain U43 (pTX35) showed qualitatively very similar phosphorylation patterns under in vitro and in vivo conditions. In vitro, it was irrelevant whether the phosphate source was orthophosphate or ATP. Inhibitors of electron transport did not inhibit light-harvesting complex I (LHIα) (B870) polypeptide phosphorylation, except for o-phenanthroline, which was strongly inhibitory. Redox conditions regulated the amount of protein phosphorylated; external redox potentials between +200 and +300 mV promoted the reaction. Phosphorylation was inhibited by uncouplers such as carbonyl cyanide m-chlorophenyl hydrazone and nigericin plus valinomycin plus potassium ions. Inhibitors of the H+-ATPase were also inhibitory when the phosphate source was [32P]Pi or [γ-32P]ATP. From these results, it was concluded that an operative reaction center, a coupled membrane, and external redox potentials higher than +200 mV are required for optimum LHIα phosphorylation. We also demonstrated that phosphorylation of LHIα polypeptide occurs before insertion into the membrane and that phosphate is preferentially incorporated into specific domains within the cytoplasmic membrane. Intracytoplasmic membranes, identified here as light membranes, were found to contain a dephosphorylated LHIα polypeptide.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Invertebrate neuroscience 1 (1995), S. 199-206 
    ISSN: 1439-1104
    Schlagwort(e): phospholipase C ; inositol phosphate ; invertebrate vision ; olfaction ; growth ; differentiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: abstract Phosphatidylinositol-specific phospholipase C (PLC) is a family of enzymes that occupy a pivotal role in one of the largest classes of cellular signaling pathways known. Mammalian PLC enzymes have been divided into four major classes and a variety of subclasses based on their structural characteristics and immunological differences. There have been five invertebrate PLC-encoding genes cloned thus far and these fall within three of the four major classes used in categorizing mammalian PLC. Four of these invertebrate genes have been cloned fromDrosophila melanogaster and one is fromArtemia, a brine shrimp. Structural characteristics of the invertebrate enzymes include the presence of highly conserved Box X and Box Y domains found in major types of mammalian PLC as well as novel features. Two of the invertebrate PLC genes encode multiple splice-variant subtypes which is a newly emerging level of diversity observed in mammalian enzymes. Studies of the invertebrate PLCs have contributed to the identification of the physiological functions of individual isozymes. These identified roles include cellular processes such as phototransduction, olfaction, cell growth and differentiation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Journal of thermal analysis and calorimetry 52 (1998), S. 537-542 
    ISSN: 1572-8943
    Schlagwort(e): fractals ; growth ; nucleation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The author presents a model based on multi-step nucleation for the heterogeneous decompositions described by nucleation and growth phenomena, taking into account the fractal nature of the nuclei.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 283-291 
    ISSN: 1572-8943
    Schlagwort(e): DSC ; fish ; general proteolytic activity ; pyloric caeca ; ripening ; salted herring product
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The thermoanalytical behaviour of pyloric caeca during salting and ripening was investigated using a Perkin Elmer DSC 7. Not only the thermal stability of the muscle proteins was influenced by salting but also that of pyloric caeca. It was recognised that the salting itself leads to a remarkable increase of the transition temperature compared with raw herring. An influence of the salt:fish ratio could be observed. The higher the salt content the higher the increase of the denaturation temperature. During ripening the transition temperature remained on a high level or showed only a slight decrease during the investigation period. The dependency from the salt content remained evident. The increase of the transition temperature was accompanied by a decrease of the transition enthalpy. The increase of thermal stability is connected with a decrease of the general proteolytic activity in pyloric caeca. Possibly, the enzymes are diffusing from the pyloric caeca into the muscle and cause there an increase of enzymatic activity observable in North Sea herring accompanied by a decrease of activity in pyloric caeca itself. Simultaneous the thermal stability of pyloric caeca is lowered. The reason for the differences in ripening could be seen in some enzyme-inhibiting factors unknown until now.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Aquaculture international 6 (1998), S. 1-17 
    ISSN: 1573-143X
    Schlagwort(e): Atlantic salmon (Salmo salar) ; Condition factor ; feeding regimes ; growth ; proximate composition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of different feeding methods on growth and slaughter traits of Atlantic salmon, Salmo salar, have been examined. Swimming activity associated with feeding was greatest amongst fish fed using automatic feeders, intermediate amongst those fed predetermined rations by hand, and least in groups of fish fed to satiation twice per day. Fish fed to satiation ate more and grew faster than did those provided with rations predicted to support high rates of growth, but the fish fed to satiation had higher feed:gain ratios than those given predetermined rations as two meals per day. The muscle tissues of the fish fed to satiation had higher lipid (%) and lower moisture (%) contents than did those of the fish fed the predetermined rations, but differences in muscle composition could be accounted for by differences in the size of the fish. Lipid was positively, and moisture negatively, correlated with fish size, whereas per cent protein and dress-out losses were little influenced by fish size and feeding regime. The fish fed to satiation were slightly heavier for a given length than those in the other groups. There was, however, no evidence that the largest fish had the highest condition factor, nor could condition factor be used to predict per cent lipid in the muscle tissue. Size variation increased in all groups of fish, and this was, in part, due to the cessation of growth of maturing individuals. Size variation was, however, most marked in the groups fed using automatic feeders, suggesting that interindividual competition for food was greatest amongst these fish.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    ISSN: 1573-143X
    Schlagwort(e): bighead carp (Aristichthys nobilis) ; growth ; Laguna Lake ; salinity tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Bighead carp (Aristichthys nobilis Oshima) fry of various ages (11, 18, and 35 days post-hatch) were exposed to the low salinities encountered during the annual intrusion of seawater in Laguna Lake, Philippines. Practical indices of salinity tolerance assessed the effect of a 96 h direct exposure to low salinities (0–16‰). Mean (MST) and median survival times (MST50) of fry decreased as salinity of rearing medium increased. Younger fry were less able to tolerate exposure to these salinities than their older cohorts. Median lethal salinity after 96 h (MLS) revealed higher tolerance among 35–day old fry (7.6‰) than 11 (2.3‰) and 18–day old fry (6.0‰), demonstrating that survival in saline water depends on their age at initial exposure to low salinities. Mean body weight of 18–day old fry reared in 0 and 2‰ for 3 and 4 weeks was higher than for those reared in 4 and 6‰ for the same period. Growth over these periods was inversely related with the range of salinities tested. These results demonstrate that, despite their known stenohalinity, bighead carp fry possess some degree of osmoregulatory capability, allowing them to survive and grow in lakes subjected periodically to saltwater inflow.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Aquaculture international 7 (1999), S. 287-293 
    ISSN: 1573-143X
    Schlagwort(e): bone mineralization ; calcium requirement ; feed efficiency ; growth ; semi-purified diet ; tiger puffer (Takifugu rubripes)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Juvenile tiger puffer (Takifugu rubripes) were fed semi-purified diets with graded levels (0–0.40%) of calcium (Ca) supplements for 8 weeks at a temperature of 23.0–25.5 °C. At the end of the feeding experiment, average final body weight increased with increasing dietary Ca levels. A diet without Ca supplement resulted in poor average final body weight and 0.05% dietary Ca supplement could not significantly improve the growth. However, supplemental Ca levels of 0.10–0.40% significantly increased growth. Dietary Ca supplements of 0.10% or more also improved the feed efficiency in tiger puffer. Ca and phosphorus contents of the bone were independent of dietary Ca supplements. However, 0.40% Ca in the diet decreased the zinc and manganese contents of bone. Results indicated that supplemental Ca levels of 0.10–0.20% in a semi-purified diet were required to maintain normal growth, feed utilization and bone mineralization of tiger puffer.
    Materialart: Digitale Medien
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 303-308 
    ISSN: 1573-2932
    Schlagwort(e): Acidification ; fish ; forestry ; water-chemistry ; management ; calcium ; aluminium ; TOC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract The soils and waters in the Galloway hills of south-west Scotland have undergone considerable acidification during the present century. The aims of this study were to examine the extent to which afforestation can influence water chemistry, and the occurrence of fish stocks within an individual catchment in this area. Studies were carried out at 45 sites in the Bladnoch catchment during 1994. River water samples were collected at all sites and determinations made of pH, total organic carbon, calcium and monomeric aluminium concentrations. In order to quantify the size and abundance of fish populations, electrofishing was carried out at 21 of the sites. Estimates of afforestation were made by a combination of field surveys and the use of 1∶:10 000 scale ordnance survey maps. The presence of coniferous trees had a substantial affect on water chemistry. In areas where the whole catchment was afforested, the water pH was 0.7 units lower than in unafforested areas (p〈0.001). Afforestation was also correlated with low concentrations of calcium, and increases in the concentrations of monomeric aluminium and total organic carbon. There was a clear relationship between fish populations and water chemistry. Numbers of trout were positively correlated with pH (r 2=0.69; p〈0.001), and with concentrations of calcium (r 2=0.55; p〈0.001). The study has shown that salmonid fish populations are sensitive to acidity and the associated changes in river water chemistry; these problems were exacerbated by afforestation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 865-870 
    ISSN: 1573-2932
    Schlagwort(e): Na+ flux ; Cl− regulation ; chloride cells ; anal papillae ; acid-sensitivity ; crustaceans ; insect larvae ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Fishes, Zooplankton, insect larvae, and benthic invertebrates differ in their sensitivity to acidic waters. Some species are able to survive and complete their life-cycle below pH 3.5 while others are eliminated once the pH drops below 5.5. Generally, acid-sensitive fauna are highly water permeable and have difficulty regulating osmotically essential ions, such as sodium and chloride, at low pH. Increased permeability during certain stages of a life-cycle (post-molt crayfish, for example) are often associated with increased acid-sensitivity. Special adaptations, including enlarged anal papillae in Chironomids and the number and morphology of chloride cells in such diverse organisms as crustaceans, insect larvae, and fishes, may enhance acid-tolerance. To test the hypothesis that Na+ regulation can be used to predict relative acid-sensitivity of aquatic fauna we will need a mechanism for standardizing Na+ regulatory capability.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 889-894 
    ISSN: 1573-2932
    Schlagwort(e): acidification ; acid neutralizing capacity ; calcite ; fish ; liming ; mitigation ; ecosystems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract The Experimental Watershed Liming Study (EWLS) evaluated the application of CaCO3, to a forested watershed to mitigate the acidification of surface water. During October 1989, 6.9 Mg CaCC3/ha was applied by helicopter to two subcatchments of about 50% (102.5 ha) of the Woods Lake watershed area. The EWLS team investigated the response to treatment of soils (chemistry and microbial processes), vegetation, wetland, stream and lake waters, and phytoplankton and fish, and applied the Integrated Lake Watershed Acidification (ILWAS) model in predicting a watershed treatment duration of up to 50 years. Observations showed a gradual change in pH, acid neutralizing capacity (ANC) and Ca2+ in the water column; direct lake additions of CaCO3 (three different times) were characterized by abrupt changes following base addition and subsequent rapid reacidification. Moreover, the watershed treatment eliminated the snowmelt acidification of the near-shore region of the lake observed during direct lake treatments. Positive ANC water in the tributary and near-shore area improved conditions for fish reproduction and for a viable fish population. Budgets for 12-month periods before and after the watershed treatment showed that the lake shifted from a source of ANC to a sink due to retention of elevated inputs of Ca2+ from the watershed CaCO3 application.
    Materialart: Digitale Medien
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Molecular and cellular biochemistry 146 (1995), S. 63-69 
    ISSN: 1573-4919
    Schlagwort(e): rice bran oil ; growth ; plasma lipids ; fatty acids ; lipoproteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract The effects of feeding two levels of rice bran oil (RBO) on the growth, lipid parameters, and fatty acid composition of the plasma and liver of rats (Wistar strain) were compared with those produced on animals which had been fed the same levels of peanut oil (PNO). The control animals were fed synthetic diets containing 5 and 20% peanut oil (PNO) and the experimental groups were fed similar diets, containing the same level of rice bran oil (RBO). There was no significant difference with respect to the organ weights between the control and the experimental groups. In general, groups fed 20% oil gained more weight than groups fed 5% oil. The animals which received rice bran oil in their diet had, in general, comparatively lower levels of cholesterol, triglycerides and phospholipids. On the other hand, animals receiving 20% rice bran oil in their diet, showed an increase of 20% in high density lipoproteins (HDL-C), within 18 weeks (p〈0.05), when compared to the animals fed with peanut oil. Similarly, low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) were lower in RBO-fed groups, than in the PNO-fed groups. There was, however, no significant differences in the cholesterol/phospholipid (C/P) ratio of the two groups. Analysis of plasma and of liver fatty acids indicated, in a general way, the type of fat consumed. There were no significant difference in the P/S ratio, nor any in the oleic/linoleic, oleic/stearic, palmitoleic/palmitic, oleic/palmitic, and oleic/palmitoleic ratios. Furthermore, levels of saturated (SAFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids were identical in both the groups. Thus, our results suggest that feeding a high level of rice bran oil (RBO) has no deleterious effect on the growth and blood lipid profile of rats.
    Materialart: Digitale Medien
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  • 37
    ISSN: 1573-4919
    Schlagwort(e): DNA adducts ; liver ; fish ; 32P-postlabelling ; polycyclic aromatic hydrocarbons ; genotoxic biomarker
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract The levels of DNA adducts in the hepatic tissue of the white sucker fish speciesCatostomus commersoni were determined by32P-postlabelling. The fish were caught at four sites: two sites near the city of Windsor (Québec, Canada) on the St. François River, a downstream tributary of the St. Lawrence River, and two sites in the St. Lawrence River itself, near the city of Montréal (Québec, Canada). The latter sites are known to be contaminated by many pollutants including polycyclic aromatic hydrocarbons. Total adduct levels in all fish ranged from 25.1–178.0 adducts per 109 nucleotides. White sucker from the selected sites of the St. Lawrence River had a significantly higher mean level of DNA adducts than those of the St. François River (129.4 vs 56.8, respectively). These results suggest that the effluents of many heavy industries (e.g. from a Soderberg aluminium plant) flowing in the St. Lawrence River are more likely to produce genotoxic damage to fish than those released in one of its tributary, and mainly associated to the activities of a small town and a nearby pulp and paper mill.
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  • 38
    ISSN: 1573-4919
    Schlagwort(e): NADH oxidase ; plasma membranes ; growth ; retinol ; retinoids ; HeLa cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract Several retinoids, both natural and synthetic, were evaluated for their ability to modulate NADH oxidase activity of plasma membranes of cultured HeLa cells and the growth of HeLa cells in culture. Both NADH oxidase activity and the growth of cells were inhibited by the naturally-occurring retinoids all trans-retinoic acid (tretinoin) and retinol as well as by the synthetic retinoids, trans-acitretin, 13-cis-acitretin, etretinate and arotonoid ethylester (Ro 13-6298). For all retinoids tested, inhibition of NADH oxidase activity and inhibition of growth were correlated closely. With tretinoin, etretinate and arotonoid ethylester, NADH oxidase activity and cell growth were inhibited in parallel in proportion to the logarithm of retinoid concentration over the range of concentrations 10-8 to 10-5 M. Approximately 70% inhibition of both NADH oxidase activity and growth was reached at 10 µM. With retinol, trans-acitretin and 13-cis-acitretin, inhibition of NADH oxidase activity and growth also were correlated but maximum inhibition of both was about 40% at 10 µM. The possibility is suggested that inhibition of the plasma membrane NADH oxidase activity by retinoids may be related to their mechanism of inhibition of growth of HeLa cells in culture. (Mol Cell Biochem 166: 101-109, 1997)
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  • 39
    ISSN: 1573-4919
    Schlagwort(e): heart ; postnatal development ; sarcoplasmic reticulum ; phospholamban ; calcium transport ; spontaneously hypertensive rats ; growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract This comparative study investigates the relationship between sarcoplasmic reticulum (SR) calcium(Ca2+)-ATPase transport activity and phospholamban (PLB) phosphorylation in whole cardiac homogenates of spo`ntaneously hypertensive rats (SHR) and their parent, normotensive Wistar Kyoto (WKY) strain during early postnatal development at days 1, 3, 6, 12 and at day 40 to ascertain any difference in SR Ca2+ handling before the onset of hypertension. At day 1, the rate of homogenate oxalate-supported Ca2+ uptake was significantly higher in SHR than in WKY (0.25 ± 0.02 vs 0.12 ± 0.01 nmoles Ca2+/mg wet ventricular weight/min, respectively; p 〈 0.001). This interstrain difference disappeared with further developmental increase in SR Ca2+ transport. Western Blot analysis and a semiquantitative ELISA did not reveal any difference in the amount of immunoreactive PLB (per mg of total tissue protein) between strains at any of the ages studied. In addition, levels of phosphorylated PLB formed in vitro in the presence of radiolabelled ATP and catalytic (C) subunit of protein kinase A did not differ between SHR and WKY at days 1, 3, 6 and 12. At day 40, C subunit-catalyzed formation of 32P-PLB was reduced by 66% (p 〈 0.001) in SHR when compared to age-matched WKY In the early postnatal period between day 1 and 12 SR Ca2+-transport values were linearly related to the respective 32P-PLB levels of both SHR and WKY rats. The results indicate that cardiac SR of SHR can sequester Ca2+ at a much higher rate immediately after birth compared to WKY rats. The disappearance of this interstrain difference with further development suggests that some endogenous neuroendocrine or nutritional factor(s) from the hypertensive mother may exert an influence upon the developing heart in utero resulting in a transiently advanced maturation of the SR Ca2+ transport function in SHR pups at the time of birth.
    Materialart: Digitale Medien
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  • 40
    ISSN: 1573-4919
    Schlagwort(e): NADH oxidase ; protein disulfide-thiol interchange ; dipyridyl-dithio substrates ; plasma membrane ; auxin ; 2,4-dichlorophenoxyacetic acid ; growth ; plant (Glycine max)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract Dipyridyl-dithio substrates were cleaved by isolated vesicles of plasma membranes prepared from etiolated hypocotyls of soybean. The cleavage was stimulated by auxins at physiological concentrations. The substrates utilized were principally 2,2′-dithiodippyrine (DTP) and 6,6′-dithiodinicotinic acid (DTNA). The DTP generated 2 moles of 2-pyridinethione whereas the 6,6′-dithiodinicotinic acid generated 2 moles of 6-nicotinylthionine. Both products absorbed at 340 nm. The auxin herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D) stimulated the activity approximately 2-fold to a maximum at about 10 μM. Concentrations of 2,4-D greater than 100 μM inhibited the activity. Indole-3-acetic acid stimulated the activity as well. The growth-inactive auxin, 2,3-dichlorophenoxyacetic acid (2,3-D), was without effect. DTNA cleavage correlated with oxidation of NADH and reduction of protein disulfide bonds reported earlier in terms of location at the external plasma membrane surface, absolute specific activity, pH dependence and auxin specificity. The dipyridyl-dithio substrates provide, for the first time, a direct measure of the disulfide-thiol interchange activity of the protein previously measured only indirectly as an auxin-dependent ability of isolated plasma membrane vesicles to restore activity to scrambled and inactive RNase.
    Materialart: Digitale Medien
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  • 41
    ISSN: 1573-4919
    Schlagwort(e): annexin V ; cardiac myocyte ; growth ; hypertrophy ; heart
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract Recently it was shown that annexin V is the most prominent member of the annexin family in the adult heart [1]. Amongst others, annexin V has been suggested to play a role in developmental processes. The aim of the present study was to explore whether in the heart annexin V content and localization change during maturational and hypertrophic growth, in order to obtain indications that annexin V is involved in cardiac growth processes. First, in the intact rat heart annexin V content and localization were studied during perinatal development. It was clearly demonstrated that annexin V content in total heart transiently increased in the first week after birth, from 0.79 ± 0.06 µg/mg protein at l day before birth to a peak value of 1.24 ± 0.08 µg/mg protein 6 days after birth, whereafter annexin V protein levels declined to a value of 0.70 ± 0.06 µg/mg protein at 84 days after birth (p 〈 0.05). Differences in annexin V content were also observed between myocytes isolated from neonatal and adult hearts [0.81 ± 0.09 and 0.17 ± 0.08 µg/mg protein, respectively (p 〈 0.05)]. Moreover, during cardiac maturational growth the subcellular localization of annexin V might change from a cytoplasmic to a more prominent sarcolemmal localization. Second, in vivo hypertrophy induced by aortic coarctation resulted in a marked degree of hypertrophy (22% increase in ventricular weight), but was not associated with a change in annexin V localization or content. The quantitative results obtained with intact hypertrophic rat hearts are supported by findings in neonatal ventricular myocytes, in which hypertrophy was induced by phenylephrine (10-5 M). In the latter model no changes in annexin V content could be observed either. In conclusion, the marked alterations in annexin V content during the maturational growth in the heart suggest a possible involvement of this protein in this process. In contrast, the absence of changes in annexin V content and localization in hypertrophied hearts compared to age matched control hearts suggests that annexin V does not play a crucial role in the maintenance of the hypertrophic phenotype of the cardiac muscle cell. This notion is supported by observations in phenylephrine-induced hypertrophied neonatal cardiomyocytes.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Aquarium sciences and conservation 2 (1998), S. 9-19 
    ISSN: 1573-1448
    Schlagwort(e): Barbus tetrazona ; nutrition ; dietary requirement-phosphorus ; growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of increasing dietary concentrations of phosphorus on growth, feeding efficiency and body composition were studied in the tiger barb (Barbus tetrazona) (Bleeker, 1855). Juvenile tiger barbs (initial weight 0.33 ± 0.02 g) were fed purified diets containing graded levels of KH2PO4 to provide 0.17–1.57% available dietary phosphorus for 8 weeks in freshwater glass aquaria. The weight gain, feeding efficiency and mineral composition of the whole body and bone were significantly (p〈0.05) affected by dietary phosphorus. Growth response data calculated by broken line analysis showed that the minimum dietary phosphorus level required for maximum growth was 0.52%. The carcass protein, fat and ash contents but not moisture were affected by various dietary phosphorus levels. Fish fed a low-phosphorus diet had high body crude fat.
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  • 43
    ISSN: 1573-1561
    Schlagwort(e): Acutilol diterpenes ; biogeography ; chemical defenses ; Dictyota ; diffuse coevolution ; fish ; plant–herbivore interactions ; sea urchin ; secondary metabolites
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Because herbivory is more intense in the tropics, tropical seaweeds may be better defended against herbivory than are temperate seaweeds. A “diffuse” coevolutionary corollary to this hypothesis is that tropical herbivores should be more resistant to seaweed defenses than temperate herbivores because tropical herbivores more commonly encounter heavily defended seaweeds. We begin to test the latter prediction using three newly discovered diterpenoid secondary metabolites from the tropical brown alga Dictyota acutiloba. We tested the feeding deterrent properties of these compounds against common herbivorous fishes and sea urchins from warm-temperate North Carolina versus tropical Guam using standardized laboratory feeding assays. The temperate herbivores were deterred by lower concentrations of secondary metabolites than the tropical herbivores. In no case was a tropical herbivore more deterred by a compound than a temperate herbivore, suggesting that temperate herbivores may be more strongly affected by seaweed chemical defenses. Feeding by the temperate pinfish Lagodon rhomboides was significantly reduced by two of the three diterpenes at a concentration that was only 13–18% of the natural concentration found in the alga. Feeding by four species of tropical fishes (two parrotfishes and two surgeonfishes) was unaffected by metabolite concentrations that deterred the temperate fish. At 100% of natural concentrations, only one of the three compounds deterred the two parrotfishes, and none of the three compounds deterred the surgeonfishes. Contrasts between the temperate sea urchin Arbacia punctulata and the tropical sea urchin Diadema savignyi showed a similar pattern; low concentrations of acutilol A acetate strongly deterred the temperate, but not the tropical, urchin. Tropical herbivores appear more resistant than temperate herbivores to seaweed chemical defenses.
    Materialart: Digitale Medien
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 25 (1999), S. 1455-1479 
    ISSN: 1573-1561
    Schlagwort(e): Turnera ulmifolia ; Euptoieta hegesia ; cyanogenesis ; Anolis sagrei ; tritrophic interactions ; host range ; sequestration ; growth ; development ; oviposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We examine the effects of the cyanogenesis polymorphism in Turnera ulmifolia on larvae, pupae, and adults of Euptoieta hegesia, the most damaging herbivore of T. ulmifolia in terms of tissue loss per unit time. We provide evidence that female E. hegesia do not show preference for host plants on the basis of their cyanogenesis level but do prefer T. ulmifolia over equally cyanogenic, closely related secondary host-plant species (Passiflora sp.). Similarly, cyanogenesis in T. ulmifolia has little effect on the food preference, growth, or development of the larvae. The potential host range of E. hegesia is limited, even within the genus Turnera, but this does not appear to be due to host-plant cyanogenesis. Pupae suffer very high mortality levels in the wild that are not associated with host-plant cyanogenesis, although our studies indicate that larvae are capable of sequestering cyanogenic glycosides from their host plants and possibly of synthesizing these or similar compounds. We provide evidence that the presence of sequestered cyanogenic compounds in the larvae protects them from terrestrial-based predators such as Anolis lizards
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 315-320 
    ISSN: 1573-2932
    Schlagwort(e): Fish populations ; perch ; roach ; growth ; reproduction ; water chemistry ; acidification ; recover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Acid-induced fish damage in small lakes in southern Finland was studied in a fish status survey of eighty lakes from 1985–1987. Later, twenty of these lakes were selected for further monitoring. A sampling of these lakes from 1988–1989 showed that the decrease in some perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) populations still continued. The results from the same lakes in 1992 showed that successful reproduction had taken place with many of the perch populations that had been close to extinction in 1985. In contrast, no signs of recovery in the roach populations were detected. The explanation for the appearance of new cohorts of perch could have been the decrease in acid deposition but the exceptional hydrological conditions of winters in the early 1990s may also have affected them. The different responses of the perch and roach populations were interpreted as a consequence of the different sensitivity of these two species to acidification. Even a slight improvement in the water quality has resulted in the appearance of strong new year-classes of perch, but not of roach. Therefore, more improvement in water quality is needed until a sensitive species like roach can reproduce again.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 823-828 
    ISSN: 1573-2932
    Schlagwort(e): fish ; mercury ; lake chemistry ; biomagnification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract We determined mercury in fish (perch Perca fluviatilis) from 26 Russian lakes in three regions over four years. The lakes ranged in size from 2 to 395,000 ha, in pH from 4.5 to 10.0, and in color from 3 to 190 hazen. Sixteen lakes were drainage lakes, with permanent outlets, and 10 were seepage lakes, with no permanent inlets or outlets. The lakes were generally located in forested regions with little or no human habitation in the watershed. The three regions were geologically distinct: Precambrian Shield granitic bedrock covered with thin soil; Triassic bedrock covered with thick glacial tills; and Triassic bedrock covered with thin sediments. At each lake water samples were collected and analyzed for pH, add neutralizing capacity (ANC), major cations, and anions. Dissolved mercury species were estimated with a thermodynamic equilibrium model (MINTEQA2). Mercury content of dorsal muscle varied from 0.04 to 1.0 μg/g wet weight, and was linearly related to calculated HgCH3Cl (r20.68, p〈0.001). Lake HgCH3Cl, in turn, was related to lake pH (r2=0.86, p〈0.001). Stepwise multiple regression selected lake HgCH3Cl and color as the factors most highly related to fish mercury content, with the model accounting for 75% of the variation.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 51-62 
    ISSN: 1573-2932
    Schlagwort(e): fish ; invertebrates ; osmoregulation ; ionoregulation ; aluminum ; calcium ; organic acids ; low pH ; acid lakes ; refugia ; mixing zones
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract This paper presents an overview of the response to acidification of aquatic fauna with special emphasis on Zooplankton, benthos, and fishes. Changes in behavior, body chemistry, reproduction, and species diversity are presented based on laboratory experiments and field studies in both Europe and North America. Differences in species sensitivity are discussed as they relate, not only to acidification but also to low calcium concentrations in the water, elevated aluminum concentrations, and presence of naturally occurring organic acids. The mechanisms—behavioral, physiological and ecological—enabling aquatic fauna to survive in acidified waters are discussed.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 419-424 
    ISSN: 1573-2932
    Schlagwort(e): acidification ; acid episodes ; critical load ; mountain ; streams ; benthic fauna ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Investigations in the southern part of the Scandinavian mountain range have shown a direct correlation between snowpack pH and the lowest pH in small streams. In streams with catchments 〈100 km2 a snowpack pH below 4.8 resulted in a stream pH below 5.5. As the snowpack pH in the southern mountain range is 4.0–4.6, lower values to the south and at high altitudes, large areas are affected by acid deposition. The acidity of the snowpack is released almost directly into the streams during thaw, due to the large snowpack, rapid thaw, steep terrain and thin soils. The acidification of the snow has lead to an extensive fauna depletion, especially in smaller streams without upstream lakes. The abundance of benthos in acidified streams in the municipality of Härjedalen (11.000 km2) is today only one tenth of the abundance before acidification. Fish populations have declined to the same extent, and several acid-sensitive species have been lost. It is concluded that mountain streams and fauna are extremely sensitive to acidification, and that even large reductions of emissions will be insufficient.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 2419-2424 
    ISSN: 1573-2932
    Schlagwort(e): critical load ; acidity ; water acidification ; soil acidification ; fish ; empirical models ; sulphur deposition ; acid episodes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract The critical load of acidity for surface waters is based on the concept that the inputs of acids to a catchment do not exceed the weathering less a given amount of ANC. The Steady State Water Chemistry (SSWC) Method is used to calculate critical loads, using present water chemistry. To ensure no damage to biological indicators such as fish species a value for ANClimit of 20 μeq/l has been used to date for calculating critical loads. The SSWC-method is sensitive to the choice of the ANClimit. In areas with little acid deposition the probability of acid episodes leading to fish kills is small even if the ANClimit is set to zero, while in areas with high acidic deposition fish kills may occur at this value. Thus, the ANClimit can be a function of the acidifying deposition to the lake, nearing zero at low deposition and increasing to higher values at higher deposition. A formulation for such an ANClimit has been worked out, and we have tested the effect of the ANClimit as a linear function of the deposition, assuming ANClimit = 0 at zero deposition with a linear increase to 50 ueq/l at a deposition of 200 meq.m−2.yr−1. For areas with high deposition the effect of a variable ANClimit is small, while in areas with low deposition the effect is significant. For Norway the exceeded area decreases from 36 to 30% using a variable ANClimit instead of a fixed value of 20 μeq/l.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 1461-1466 
    ISSN: 1573-2932
    Schlagwort(e): ozone ; wheat ; Triticum aestivum ; growth ; senescence ; biomass partitioning ; photosynthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract In closed-chamber fumigation experiments dry matter partitioning and chlorophyll fluorescence of wheat were studied, analysing the effects of ozone during different stages of plant development. Ozone causes enhanced leaf senescence, leading to a loss of green leaf area and, consequently to a decreased supply of assimilates, affecting (in increasing order of severeness) stem, ear and grain productivity because of reduced storage pools for translocation. Leaves of plants before shooting stage were most sensitive but the lack of green leaf area after ear emergence had the most pronounced effects on grain yield. Measurements of photochemical capacity showed that evidence for negative ozone effects could be found in changes of chlorophyll fluorescence parameters in leaf sections not yet showing visible ozone injury. Negative effects on photosynthesis were more distinct with increasing accumulated ozone dose, with increasing age of leaf tissue and with increasing ozone sensitivity of the cultivar. The changes in chlorophyll fluorescence are most likely to be explained by a decreased pool size of plastoquinones caused by ozone.
    Materialart: Digitale Medien
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 90 (1996), S. 557-562 
    ISSN: 1573-2932
    Schlagwort(e): heavy metal ; accumulation ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Levels of cadmium, copper, zinc, lead and iron were determined seasonally in the liver, spleen, kidney, gill and muscle tissues of Mullus barbatus and Sparus aurata from the Iskenderun Gulf, East Mediterranean coast of Turkey. Wet digested tissues were analysed by atomic absorption spectroscopy. Metal levels were higher in liver, spleen and kidney compared with the gill and muscle tissues in both species; the levels of all metals in a given tissue were always higher in Mullus barbatus than in Sparus aurata.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 94 (1997), S. 163-180 
    ISSN: 1573-2932
    Schlagwort(e): acid deposition ; liming ; catchment ; lake ; water chemistry ; fish ; soil ; model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract In June 1983 a whole-catchment liming experiment was conducted at Tjønnstrond, southernmost Norway, to test the utility of terrestrial liming as a technique to restore fish populations in remote lakes with short water-retention times. Tjønnstrond consists of 2 small ponds of 3.0 and 1.5 ha in area which drain a 25-ha catchment. The area is located at about 650–700 meters above sea-level in sparse and unproductive forests of spruce, pine and birch with abundant peatlands. A dose of 3 ton/ha of powdered limestone were spread by helicopter to the terrestrial area. No limestone was added to the ponds themselves. The ponds were subsequently stocked with brown and brook trout. Liming caused large and immediate changes in surface water chemistry; pH increased from 4.5 to 7.0, Ca increased from 40 to 200 μeq/L, ANC increased from –30 to +70 μeq/L, and reactive-Al decreased from about 10 to 3 μmol/L. During the subsequent 11 years the chemical composition of runoff has decreased gradually back towards the acidic pre-treatment situation. The major trends in concentrations of runoff Ca, ANC, pH, Al and NO3 in runoff are all well simulated by the acidification model MAGIC. Neither the measured data nor the MAGIC simulations indicate significant changes in any other major ion as a result of liming. The soils at Tjønnstrond in 1992 contained significantly higher amounts of exchangeable Ca relative to those at the untreated reference catchment Storgama. In 1992 about 75% of the added Ca remains in the soil as exchangeable Ca, 15% has been lost in runoff, and 10% is unaccounted for. The whole-catchment liming experiment at Tjønnstrond clearly demonstrates that this liming technique produces a long-term stable and favourable water quality for fish. Brown trout in both ponds in 1994 have good condition factors, which indicate that the fish are not stressed by marginal water quality due to re-acidification. The water quality is still adequate after 11 years and 〉20 water renewals. Concentrations of H+ and inorganic Al have gradually increased and approach levels toxic to trout, but the toxicity of these are offset by the continued elevated Ca concentrations. Reduced sulphate deposition during the last 4 years (1990–94) has also helped to slow and even reverse the rate of reacidification. The experiment at Tjønnstrond demonstrates that for this type of upland, remote terrain typical of large areas of southern Norway, terrestrial liming offers a suitable mitigation technique for treating acidified surface waters with short retention times.
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  • 53
    ISSN: 1573-3017
    Schlagwort(e): cortisol ; BKME ; fish ; interrenal ; pituitary ; morphol ogy ; acute stress ; endocrine dysfunction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract The effects of bleached kraft mill effluent (BKME) on blood cortisol levels and the morphology of the pituitary-interrenal axis were investigated in two species of teleost fish, the northern pike, Esox lucius, and the yellow perch, Perca flavescens, sampled upstream and downstream from a pulp and paper mill on the St Maurice River, Quebec. Fish were acutely stressed by a standardized capture and sampling protocol at both sites, and their ability to elevate blood cortisol levels in response to the capture stress was compared. Blood cortisol levels in fish from the upstream site (〉100 ng/ml plasma) were higher than the levels in fish from the BKME site, and the pituitary corticotropes and the interrenal steroidogenic cells of the upstream fish were larger and had larger nuclei compared with cells from the downstream fish. The low blood cortisol levels in fish exposed to BKME were correlated to cellular atrophy within the hypothalamo-pituitary-interrenal (HPI) axis. The reduced ability to elevate blood cortisol in response to an acute stress may be an endocrine dysfunction occuring in fish chronically exposed to chemical stressors in their environment
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  • 54
    ISSN: 1573-3017
    Schlagwort(e): fish ; mercury ; natural selection ; allozyme ; population
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Measurements of the differential tolerance between enzyme genotypes and shifts in allozyme frequencies in populations from contaminated habitats have prompted the use of allozymes as markers of population-level toxicant effects. However, such studies often do not consider other factors that influence allele frequencies, including natural clines, migration, the intensity and specificity of selection and toxicant-induced genetic bottlenecks. In addition, selection components other than survival are not included. Consequently, the associated conclusions remain speculative. To assess this approach rigorously, a simulation study was conducted with the mosquitofish (Gambusia holbrooki) GPI-2 locus. Laboratory studies have shown the GPI-238/38 homozygote at this locus to be less tolerant than other genotypes during acute exposure to mercury. The GPI-2100/100 genotype has also been shown to have a reproductive disadvantage at lower mercury concentrations. Simple and then more complex models were used to quantify the relative effects of viability selection, random genetic drift and migration on the GPI-238 allele frequency. Simulations were also performed to assess the contribution of sexual and fecundity selection. A simple population model suggested that viability selection plays a greater role than does mortality-driven, genetic drift in the decrease of the sensitive allele under the conditions of this study. A more complex, stochastic model indicated that no significant mortality-driven drift was taking place in this system. In both models, migration mitigated the effect of selection. Sexual and fecundity selection had little effect on the allele frequencies in these simulations. We conclude that, provided the system under study is clearly understood, shifts in allele frequency can indicate the population-level effects of pollutants.
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  • 55
    ISSN: 1573-3017
    Schlagwort(e): genotoxicity ; Chernobyl ; fish ; flow cytometry ; coefficient of variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Flow cytometric (FCM) analysis was used to assess the potential impact of chronic radionuclide exposure in fish populations inhabiting contaminated sites in the vicinity of the Chernobyl nuclear accident. Four species of fish, channel catfish (Ictalurus punctatus), crucian carp (Carassius carassius), carp (Cyprinus carpio) and tench (Tinca tinca), were collected within a 10 km radius of the Chernobyl Nuclear Power Plant and compared with 'control' populations from two uncontaminated locations far removed from the plant. Assays of whole blood, as well as separate erythrocyte and leukocyte components, revealed aneuploid-like patterns in the DNA histograms of some fish, as well as widened G0/G1 peaks. None of the fish collected from the uncontaminated sites demonstrated these kinds of changes in their DNA histograms. Increases in the coefficient of variation (CV) of the G0/G1 peak, indicating abnormal DNA distributions, were observed in several of the fish from Chernobyl relative to the control populations. Cell cycle perturbation in fish from the contaminated sites was also detected, with a higher percentage of cells in G2/M phase relative to the controls. Leukocytes proved more sensitive than erythrocytes, as they displayed a larger number of abnormal DNA histograms. Variations in the cellular DNA content similar to those reported here have been shown for other vertebrate species exposed to radiation and other genotoxic agents in laboratory and field settings.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    ISSN: 1573-3017
    Schlagwort(e): contamination risks ; fish ; Mississippi River ; ecological factors ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract We compared contamination levels in fish from contaminated and uncontaminated floodplain swamps of the lower Mississippi River to assess differences in contamination risks between swamps, across different taxonomic and ecological groupings of fishes within and between swamps, and with seasonality in river stage. Fish tissue levels of inorganic contaminants were substantially lower than environmental levels in both swamps, suggesting either that fish were not uptaking these contaminants, or they were effectively eliminating the contaminants from their bodies. Tissue levels of organic contaminants were high relative to environmental levels, suggesting that these contaminants were bioaccumulating. Organic contaminants were significantly higher in fish from the contaminated swamp (Devil's Swamp) than in fish from a reference swamp up river (Tunica Swamp). Because the organic contaminants were largely confined to sediments, we expected bottom-oriented fishes to have higher concentrations than pelagic fishes. Assuming that uptake was primarily through the food chain, we expected top predators to exhibit higher concentrations than low-level consumers. We also expected year- round swamp residents to exhibit higher accumulations than more transitory users of backswamp habitat. However, organic contaminant levels did not differ in the directions expected for any of these groupings. We did observe differences in organic contaminant levels within and between swamps for different taxonomic groupings of fishes (species and genera). Some taxa occupying low to middle positions in the food web (e.g., gizzard shad, Lepomis spp.) exhibited higher concentrations than taxa near the top of the food web. Within Devil's Swamp, organic contaminant levels were significantly higher at low river stage, when fish were confined to the swamp, than at high river stage, when fish were free to move between the river and the swamp. We caught more species and more fish per unit effort in Devil's Swamp than in Tunica Swamp, contrary to expectations if contaminants in the former were negatively impacting population and community structure. Species richness differences between swamps were a consequence of catch differences, with higher catch corresponding to inclusion of more rare species. The lower catch in Tunica Swamp may have resulted from physical modifications of its waterways to support agriculture and hunting. The results of this study underscore the importance in factoring information on the taxonomy and ecology of organisms, and seasonal changes in environmental conditions, into assessments of contamination risks.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    ISSN: 1573-3017
    Schlagwort(e): Tubifex tubifex ; sediment bioassay ; hormesis ; growth ; reproduction ; egestion rates
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Toxicity assessment based on sediment chronic bioassays with the aquatic worm Tubifex tubifex was performed at ten contaminated sites in the industrial area of Bilbao (Northern Spain). One control and three reference sites were also included. Tubifex bioassay measures both survival and reproduction impairment. These endpoints have been contrasted and discussed in relation to somatic growth and both individual and total biomass of cocoons. Survival was only affected at one site which was heavily contaminated by organic compounds, mainly PAHs. A group of four severely ecotoxic sediments was characterised by a drastic reduction in number and size of cocoons, and adult somatic growth. In other group of sediments, some significant increases were found for these variables. It is suggested that these increases represent an effect of hormesis. An index of reproductive effort was used to integrate the relationship between somatic growth and reproduction. Values of reproductive effort at the test sediments were lower than those at the control sediment, suggesting a conservative strategy of oligochaete worms which consisted in an investment into somatic line (growth) at the expenses of offspring. Rates of food consumption which were estimated from egestion rates, were low at the contaminated sites. This fact could be related to the low production levels found at these sites and may reflect avoidance feeding behaviour of the oligochaete worms within the sediments. At some reference sites, high production could have resulted from high nutritional quality of sediments, or to an hormetic effect due to low concentration of some chemicals. Results are discussed in relation to toxicity data from sediment three-brood bioassay with Daphnia magna Straus performed separately on the same sediments.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 58
    ISSN: 1573-3017
    Schlagwort(e): fish ; speciation ; copper ; bioavailability ; bioaccumulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Neon tetras Paracheirodon innesi were exposed to various species of copper during exposures to evaluate the bioavailability of free copper (0 to 2 mg/l), copper apparently complexed to humic substances (0 to 160 mg/l), and copper adsorbed on kaolin clays (0 to 182 mg/l). The results of the experiments demonstrated that free copper is the most bioavailable form. Both humic substances and kaolin clay particulates reduced copper bioavailability to the fish. However, fish accumulated a fraction of copper complexed to humic substances and part of copper adsorbed on kaolin clays.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Molecular biology reports 21 (1995), S. 85-86 
    ISSN: 1573-4978
    Schlagwort(e): fish ; repetitive DNA ; SINE ; LINE
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A highly repetitive DNA element has been isolated fromOpsariichthys uncirostris. It contains several oligo-dA tracts and potential regions for the secondary structures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Molecular biology reports 22 (1995), S. 33-35 
    ISSN: 1573-4978
    Schlagwort(e): fish ; repetitive DNA ; RFLP ; satellite DNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A member of satellite repetitive DNA was isolated and sequenced from a saltwater fishSillago japonica (Percoidei). This sequence consists of several oligo-dA/dT tracts and two inverted repeats which resemble each other. Dot blot hybridization analysis using a satellite DNA clone pSJ2 among the species in the suborder Percoidei revealed that the pSJ2 sequence was amplified at least after the family Sillaginidae had been derived.
    Materialart: Digitale Medien
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  • 61
    ISSN: 1432-0878
    Schlagwort(e): Key words Neurotrophins ; Trk receptors ; Nervous system ; Endocrine cells ; Gut ; fish ; Teleosts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Neurotrophins, acting through their high-affinity signal-transducing Trk receptors, are involved in the development, differentiation and maintenance of discrete neuron populations in the higher vertebrates. Furthermore, the presence of Trk receptors in some non-neuronal tissues, including the endocrine cells of the gut, could indicate an involvement of neurotrophins also in these tissues. Recently, neurotrophins and neurotrophin receptor proteins have been identified in the lower vertebrates and invertebrates, whose amino acid sequences are highly homologous with those found in mammals. The present study investigates the occurrence and distribution of Trk-like proteins in the neurons and gut endocrine cells in five species of teleost. Single and double immunolabeling was carried out on fresh and paraffin-embedded tissue using commercially available antibodies against sequences of the intracytoplasmic domain of the mammalian Trk. Western-blot analysis, carried out on samples of stomach and intestine of bass, identified proteins whose estimated molecular masses (140 kDa, 145 kDa and 143–145 kDa) were similar to those reported for full-length TrkA, TrkB and TrkC in the higher vertebrates. TrkA-like immunoreactivity was found in the enteric nervous system plexuses of three fish species. Trk-like immunoreactivity was observed in the endocrine cells as follows: sparse TrkA-like immunoreactive endocrine cells were detected only in the intestine; TrkB-like immunoreactive cells were detected only in the stomach; and TrkC-like immunoreactive cells were found both in the intestine of the carp and in the stomach of the bass, where they also showed TrkB-like immunoreactivity. These findings confirm the occurrence and distribution of Trk-like proteins in teleosts. These proteins are closely related to the Trk neurotrophin receptors of mammals. The functional significance of Trk-like proteins in both neuronal and non-neuronal cells of teleosts is still not clear.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    ISSN: 1432-0878
    Schlagwort(e): Key words: Aesthetasc ; Chemoreception ; Dendrite Blue crab ; growth ; Olfaction ; Salinity adaptation ; Sensilla ; Callinectes sapidus (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The aesthetasc sensilla of the euryhaline blue crab, Callinectes sapidus, are innervated by the dendrites of from 40 to 160 bipolar chemosensory neurons. Each dendrite forms two cilia within the basal portion of the sensillum, and these subsequently branch yielding approximately 10 outer dendritic segments per neuron. Auxiliary cells surround the inner dendritic segments and also ensheathe the outer dendritic segments up to the terminus of the ”constricted region” (a zone in which there is a slight narrowing of the aesthetasc). Crystal violet staining suggesting access of odor stimuli is limited to that portion of the sensillum distal to the constricted region. In freshwater-acclimated blue crabs the length and level of branching in the dendrites extending beyond the constricted region is significantly reduced relative to that of seawater-acclimated animals (mean lengths: 150 µm versus 517 µm, respectively). After transfer of freshwater-acclimated crabs to seawater there is a rapid increase in length of the outer dendritic segments, reaching 60% of that for seawater-acclimated crabs by 48 h. A similar time course for regrowth is seen for seawater-acclimated crabs in which the outer dendritic segments have been osmotically ablated. Conversely, with rapid transfer of seawater-acclimated animals to lower salinities, there is a correspondingly rapid reduction in length of the outer dendritic segments. The reduced length of the outer dendritic segments in freshwater-acclimated animals may reflect the effective distance over which an appropriate osmotic/ionic microenvironment for neural function can be maintained within the aesthetasc.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 39 (1996), S. 165-178 
    ISSN: 1871-4528
    Schlagwort(e): Solanum tuberosum L. ; temperature stress ; growth ; nutrient deficiency ; tuber analysis ; tuber size ; glasshouse ; growth room
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary To determine calcium fertility and high temperature effects on internal brown spot development in potato, cv. Russet Burbank plants were fertilised with Hoagland's nutrient solution with or without calcium. Prevalence and severity of internal brown spot were greatest in tubers receiving no calcium fertilisation during growth. Internal brown spot was evident as early as tuber initiation. A high growth medium temperature (32°C) at tuber maturity with a lack of calcium increased internal brown spot incidence and severity. No tubers subjected to the high temperature and fertilised with calcium developed internal brown spot. Peel calcium concentration of tubers receiving no calcium fertilisation was lower (0.5–0.8 g/kg) than tubers receiving calcium (1.2–1.9 g/kg). Medullary tissue calcium concentration was similar under both calcium regimes. Calcium availability during early tuber growth was an influential factor in internal brown spot development, however high temperature effects may not be discounted in exacerbating the disorder.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Transgenic research 6 (1997), S. 59-67 
    ISSN: 1573-9368
    Schlagwort(e): Sparus aurata ; transgenic ; ecologicalrisk ; release ; genetic modification ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In support of the emerging industries of warmwater marine fish mariculture, genetic engineering and classical genetic improvement programmes have been initiated for a variety of exclusively marine fish. These programmes have the potential to perturb allele and genotype frequencies, or introduce novel alleles and genes into conspecific wild populations. Despite concerns to the contrary, the following hypothesis remains to be falsified: ‘laboratory induced allele frequency/genotype changes and novel alleles or genes have a negligible probability of being selectively favoured in wild populations under natural selection, and accordingly, without sustained large scale releases, have little potential for ecological impact’
    Materialart: Digitale Medien
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 196 (1995), S. 195-206 
    ISSN: 1615-6110
    Schlagwort(e): Pteridophyta ; Dryopteridaceae ; Dryopteris filix-mas ; Clonal gametophytes ; growth ; reproduction ; genetic and environmental effects ; phenotypic plasticity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Artificially formed clonal gametophytes ofDryopteris filix-mas (L.)Schott were able to grow and reproduce, although growth rates, proportions of hermaphrodites and reproductive efforts were low. Variable density and nutrient levels appeared to affect gametophytic life histories and they continued to influence the viability of the developing sporophyte generation. Differences between populations and sporophytes were discovered in life histories. Hermaphroditic gametophytes were considerably larger and possessed higher viability than did males. Clear differences between clones in the level of phenotypic plasticity in gametophyte size were observed. No neighbor effect on gametophyte sex expression was detected with the densities and nutrient levels used.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Aquatic ecology 33 (1999), S. 287-292 
    ISSN: 1573-5125
    Schlagwort(e): community analysis ; estuary ; fish ; nursery
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Tagus estuary has long been subjected to several human activities and uses. Changes in the estuarine fish community were evaluated based on beam trawl surveys in 1978–1980 and 1994–1996. There was a decrease of abundance of many species that use the Tagus as a nursery, namely bib (Trisopterus luscus), five bearded rockling (Ciliata mustela), tub gurnard (Trigla lucerna), and flounder (Platichthys flesus), possibly due to reduction of the water quality. In 1994–1996, only sea bass (Dicentrarchus labrax), sole (Solea solea) and Solea senegalensis Kaup, 1858, were found within the nursery grounds, showing an irregular pattern of abundance. Condition and vacuity index were highly variable. The major problems affecting the fish community, namely pollution, fishery regulation and waterflow regulation, are discussed in relation to the management and conservation of this estuarine system.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    ISSN: 1573-5176
    Schlagwort(e): Debromolaurinterol ; growth ; Laurencia ; laurinterol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The growth of Laurencia okamurae and the content of laurinterol and debromolaurinterol were influenced by various factors. Temperature influenced growth raere te with a maximum at 25°C, regardless of daylength. Maturity depended on temperature rather than daylength; the plants grew without maturing at 15°C, while the plants matured within two weeks at 25°C. The plants were able to grow at salinities of 14–50‰ with maximum growth at 26‰. The salinities growth rash;50‰te reduced with decreasing concentration of nitrate below 1.2 × 10-3 M, and of total phosphate below 7.5× 10-8 M. Bromide concentration had no effect on growth, and the plants grew without bromide. Variation in temperature between 15–25°C and daylength produced no obvious change in laurinterol and debromolaurinterol contents. On the other hand, an increase in salinity led to an increase for both. The plants cultured in a completely artificial medium, modified ASP12NTA, showed a marked drop in their content of these metabolites. An increase in concentrations of nitrate, total phosphate or bromide did not restore the content.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 10 (1998), S. 547-554 
    ISSN: 1573-5176
    Schlagwort(e): herbicide ; green alga ; growth ; nutrients ; photosynthesis ; it Protosiphon botryoides ; respiration ; Thiobencarb
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of the herbicide thiobencarb (Saturn) were tested on the growth and physiology of the chlorophyte Protosiphon botryoides isolated from an Egyptian paddy. Assays were conducted using 16-day batch cultures. Chlorophyll and dry weight biomass yields were significantly reduced at 2–3 mg L-1 thiobencarb, and dark respiration increased and protein decreased significantly at 3 mg L-1. Reductions in exponential specific growth rate (μ) were generally small, but in some cases significant. Thiobencarb also slightly, but significantly, reduced the 77 K fluorescence parameter Fv/Fm, an indicator of maximum photosynthetic efficiency. No consistent dose-dependent changes occurred in chlorophyll per unit dry weight, total carbohydrate or gross photosynthetic capacity. Whereas half of the added thiobencarb was recovered from control (uninoculated) medium, it was largely absent from cells and culture medium after sixteen days, indicating biodegradation by the alga or associated bacteria. P. botryoides recovered fully within sixteen days following subculture in thiobencarb-free medium. Independently varying phosphate and nitrate nine-fold had no clear effect on the sensitivity of P. botryoides to thiobencarb.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    ISSN: 1573-5176
    Schlagwort(e): agar ; Gracilaria tenuistipitata ; growth ; salinity ; seawater pH
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Acclimation responses of the red alga Gracilaria tenuistipitata var. liui collected on the northwest coast of Philippines were determined in laboratory setups and outdoor cultivation tanks in Haifa, Israel. Growth under laboratory conditions was influenced by all three variables studied, namely, temperature (20 or 30 °C), salinity (20, 30 or39‰) and seawater pH (6.5, 7.0, 8.0 or ≥ 9.0). In 250 mL flasks lacking pH control growth was influenced by temperature only at 20 ‰, whereas at 39 ‰, growth rates were similar at 20 or 30 °C. In 500 mL cylinders in which pH was controlled, growth rates were significantly different at a pH of 6.5 and 7.0 for all salinities, with maximal rates occurring in 39 ‰. At pH 8.0, and above, growth rates between salinities were similar and reduced to approximately 50% at a pH of 9.0 compared to rates at a pH of 6.5. Photosynthesis responses generally resembled growth responses both, in 250 mL and 500 mL cultures. In 40-L outdoor tanks, weekly growth and agar yields were apparently enhanced by increasing light intensities (up to full sunlight) and nutrient concentrations (up to 0.2 mM PO3 2- and 2.0 mM NH4 +), and rates averaged four times higher than rates determined in the smaller flask cultures. This study shows broad salinity tolerance of G. tenuistipitata var. liui and its ability to sustain growth rates that are among the highest measured for Gracilaria spp. in outdoor cultures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 70
    ISSN: 1573-5125
    Schlagwort(e): growth ; Azolla ; eutrophication ; mercury ; India
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The growth ofAzolla was stimulated in different water bodies in Burdwan. It depended on the PO4−P contents of the media. Biomass, chlorophyll and tissue phosphorus content ofAzolla were positively correlated with PO4−P of the different water bodies while chlorophyll content of the fern was positively correlated with conductivity. We concluded that the water bodies of Burdwan can be utilised as sites for large scale multiplication ofAzolla for fertilization purposes in rice cultivation, despite the presence of mercury.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 9 (1997), S. 19-24 
    ISSN: 1573-5176
    Schlagwort(e): Chaetoceros ; growth ; neutral lipid ; total lipid ; nitrogen deprivation ; Nile Red
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Chaetoceros muelleri (Schütt) was cultured on a thermal gradient plate, subjected to two media types with a range of specific conductances, and evaluated for growth and neutral lipid accumulation. Growth was measured directly by daily changes in cell numbers and indirectly by changes in optical density at 750 nm. C. muelleri exhibited a growth rate of at least two doublings day-1 over broad temperature (20 to 35 °C) and conductance ranges (10 to over 60 mS cm-1) and the optimum growth rate approached 4.0 doublings day-1 at 30 °C and a conductance of 25 mS cm-1. Intracellular neutral lipid storage was evaluated with fluorometry and epifluorescent microscopy using the fluorochrome Nile Red. Gravimetric analysis revealed a total lipid content in nitrogen-depleted cultures of C. muelleri of over 400 mg L-1, five to seven times that observed in nitrogen-replete cultures. Based on its high growth rate, tolerance to a broad range of temperatures and specific conductances, and large quantity of intracellular lipid, C. muelleri may have potential for exploitation as a renewable precursor to liquid fuels or as a lipid source.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 9 (1997), S. 437-444 
    ISSN: 1573-5176
    Schlagwort(e): Haematococcus pluvialis ; experimental design ; optimization ; culture medium ; growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A central composite rotatable design was used to examine the effects of five components of the medium on the growth of Haematococcus pluvialis in batch culture. The medium components considered were: sodium acetate,potassium nitrate, major elements, trace elements and vitamins. Within the range of the concentrations tested, a moderate concentration of the major elements significantly enhanced algal growth, both in terms of specific growth rate and cell dry weight, whereas the vitamins had no significant effect. Based on the response surface contour plots and the results of numerical analyses, the optimal nutrient concentrations for growth in terms of specific growth rate were 0.51 g L-1 sodium acetate, 0.25 g L-1 potassium nitrate, 0.63 mL L-1 of the major element stock solution and 0.2 mL L-1 of the trace element stock solution. The optimal nutrient concentrations for biomass production were 1.64 g L-1 sodium acetate, 0.37 g L-1potassium nitrate, 2.52 mL L-1 of the major element stock solution and 0.03 mL L-1 of the trace element stock solution.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 9 (1997), S. 551-558 
    ISSN: 1573-5176
    Schlagwort(e): Spirulina ; Arthrospira ; growth ; salinity ; quantum yield ; nutrient status ; Chitu ; Ethiopia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Spirulina platensis (=Arthrospira fusiformis) was isolated from Lake Chitu, a soda crater lake in the Ethiopian Rift Valley, where it formsa dense and almost unialgal population. Growth experiments were run in turbidostats under constant light, to assess growth response and tolerance to salinity, as well as to the component anions. Salinity was tested over the range 13–88 g L-1 using additions of NaHCO3, NaCl or Na2SO4. A maximum specific growth rate (µmax d-1) of 2.14 was achieved at the lowest salinity, but quantum yield (Φ%) was highest between 33 to 51 g L-1. Increasing salinity of the medium reduced the specific growth rate (µ) to a minimum of 0.33 d-1, and Φ to 〈 0.5%. Growth response in terms of µ and Φ was best in HCO 3 - , less in Cl-, and least in SO 4 2- series. Cultures showed obvious differences in cellular morphology, pigment, nitrogen and phosphorus contents in response to treatment with the different anions. Results indicate that the species has a wide range of tolerance to salinity from NaHCO3. Some degree of tolerance is also shown to high concentrations of Cl- and SO 4 2 , but with an overall lower performance of cells in terms of growth rate, light utilization efficiency, and nutrient status to cells grown in high HCO 3 - concentrations and the same levels of salinity and light.
    Materialart: Digitale Medien
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  • 74
    ISSN: 1573-5125
    Schlagwort(e): eutrophication ; feeding ; growth ; Mytilus edulis ; validation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract EMMY is an ecophysiological model of the growth and reproduction of a single mussel (Mytilus edulis L.). It contains feedback loops in the uptake and metabolism of food and in the partitioning of carbon and nitrogen to the internal state variables somatic tissue, storage, organic shell matrix and gametes. In this paper EMMY is used to simulate individual mussel growth in a series of mesocosm experiments with different inorganic nutrient loads (N and P). The experiments explore the impact of eutrophication reduction scenarios on mussel growth under defined and controlled conditions. In earlier studies EMMY was calibrated using expert knowledge on growth and reproduction during a period of 5 years. The resulting calibrated model was validated for system inputs and observations of three ecosystems with significantly different food and silt concentrations. EMMY reproduced the mussel growth sufficiently accurate in ecosystems with moderate or high food concentrations. In this study EMMY was adapted in order to cope with low food concentrations, then recalibrated (using the original calibration data and procedure) and applied without further calibration to 3 replicated mesocosm experiments. The EMMY simulations in this study show the ecophysiological response of mussels to different food (phytoplankton and detritus) concentrations. It is concluded that the mussels can adapt to significantly reduced food concentrations, due to inorganic nutrient load reduction, and still maintain growth.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 8 (1996), S. 421-430 
    ISSN: 1573-5176
    Schlagwort(e): Gracilaria gracilis ; suspended cultivation ; vegetative propagation ; South Africa ; yield ; growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Rope rafts were used to evaluate the growth of localGracilaria gracilis at Saldanha Bay, on the west coast of South Africa, over four years. The plants were grown on horizontally-suspended ropes or netting lines. Relative Growth Rates (RGR) of plants on ropes with low stocking weights often exceeded 10% d−1 in (austral) summer, and fell to between 6 and 7.5% d−1 in winter. Commercial-style lines of plastic netting stocked at 400 g m−1 and placed 0.75 m apart yielded a mean of about 2 kg m−2 30 d−1, with a mean RGR of about 5% d−1 over a two-year period. Various methods of improving yields were tested, including attaching floats to individual lines and optimising stocking weight. In Saldanha Bay in late summer, warm, oligotrophic water can severely reduce growth. Growth was optimised by growing the plants as close as possible to the surface (0.2 m), where water motion, and by implication, nutrient uptake, are higher. Agar content and gel strength generally remained high all year round. The potential for commercial production is evaluated in the light of these results.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Cytotechnology 29 (1999), S. 1-10 
    ISSN: 1573-0778
    Schlagwort(e): batch culture ; conditioned medium ; growth ; hybridoma ; inoculum ; protein productivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Apart from gas concentrations, temperature, and pH, generally only the initial conditions can be manipulated in batch culture. Inoculum size and initial conditioned medium concentration represent two important considerations for optimal batch production. Two hybridoma cell lines were used to assess the impact of these initial conditions on population growth and monoclonal antibody productivity in suspension batch culture. Varying initial cell concentration over the range of 1.0 × 105 cells mL-1 to 3.0 × 105 cells mL-1 did not affect maximum product titre or maximum volumetric cell-hours attained. Initial percent of conditioned medium up to 40 percent strongly impacted on population growth and productivity, with initial levels of 30 to 40% conditioned medium reducing or eliminating lag phase and increasing average viable cell density. However, specific productivity and product titre declined with increasing initial percent conditioned medium, even on a per volume of fresh medium basis. Glutamine and glucose depletion or ammonia toxicity could cause depressed product titres when conditioned medium is used. Glutamine and glucose levels can easily be replenished in conditioned medium at minimal cost, and ammonia can be removed. Specific productivity was higher during cyclic batch operating mode than during batch operating mode. This may be because cyclic batch operating mode results in an incidental volume of conditioned medium at the beginning of each cycle. A two stage, cyclic-batch/batch operating mode can be employed to fully utilize medium and maximize product titre.
    Materialart: Digitale Medien
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  • 77
    ISSN: 1573-1464
    Schlagwort(e): abundance ; bioindicators ; fish ; hybridization ; impact ; invasion models ; invasional meltdown ; invasions ; models ; nonindigenous species ; range
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Although ecologists commonly talk about the impacts of nonindigenous species, little formal attention has been given to defining what we mean by impact, or connecting ecological theory with particular measures of impact. The resulting lack of generalizations regarding invasion impacts is more than an academic problem; we need to be able to distinguish invaders with minor effects from those with large effects in order to prioritize management efforts. This paper focuses on defining, evaluating, and comparing a variety of measures of impact drawn from empirical examples and theoretical reasoning. We begin by arguing that the total impact of an invader includes three fundamental dimensions: range, abundance, and the per-capita or per-biomass effect of the invader. Then we summarize previous approaches to measuring impact at different organizational levels, and suggest some new approaches. Reviewing mathematical models of impact, we argue that theoretical studies using community assembly models could act as a basis for better empirical studies and monitoring programs, as well as provide a clearer understanding of the relationship among different types of impact. We then discuss some of the particular challenges that come from the need to prioritize invasive species in a management or policy context. We end with recommendations about how the field of invasion biology might proceed in order to build a general framework for understanding and predicting impacts. In particular, we advocate studies designed to explore the correlations among different measures: Are the results of complex multivariate methods adequately captured by simple composite metrics such as species richness? How well are impacts on native populations correlated with impacts on ecosystem functions? Are there useful bioindicators for invasion impacts? To what extent does the impact of an invasive species depend on the system in which it is measured? Three approaches would provide new insights in this line of inquiry: (1) studies that measure impacts at multiple scales and multiple levels of organization, (2) studies that synthesize currently available data on different response variables, and (3) models designed to guide empirical work and explore generalities.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 11 (1999), S. 293-299 
    ISSN: 1573-5176
    Schlagwort(e): organismic determinants ; Gracilaria gracilis ; Rhodophyta ; regeneration ; growth ; mariculture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The growth of Gracilaria gracilis (Stackhouse) Steentoft, Irvine et Farnham was examined by studying the effect of organismic determinants such as thallus length, position along the thallus and branching. Knowledge of these factors is essential in order to increase production from suspended seaweed rafts seeded with vegetative G. gracilis fragments. Seeding netlons with seaweed material freshly collected from subtidal populations provided up to 30% higher relative growth rates than seaweed maintained on the netlons for successive months. Initial seedstock length greatly affected growth rates and yields such that 30-cm thalli fragments resulted in growth rates 14% higher than for 10-cm fragments. This difference is suggested to be due to the higher contribution to overall biomass by growth of lateral branches. Comparisons of the growth of apical and basal fragments suggest that growth takes place over the entire length of the thallus, but that the apex contributes more to overall elongation than does the proximal part. The removal of apical meristems resulted in an enhanced branching frequency with production of four times as many branches as intact fragments. Evidence is also provided for extensive morphological differentiation following long periods of rapid growth. These thalli have very high frequency of branching, are hollow due to the disintegration of medullary cells and are considered to be completely senescent. These factors have implications for the successful cultivation of G. gracilis on commercial mariculture systems.
    Materialart: Digitale Medien
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  • 79
    ISSN: 1573-5125
    Schlagwort(e): Marenzelleria ; Polychaetes ; macrozoobenthos ; abundance ; biomass ; population dynamics ; growth ; secondary production ; Baltic Sea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The propagation of an immigrant from North America, viz. the spionid Marenzelleria cf. viridis in the Darss-Zingst Bodden (DZB) (southern Baltic Sea), was studied at three stations from March 1992 to December 1995. Highest mean abundances (over 28 000 ind. m-2) and wet weights (400 g m-2) were recorded at station 2 in 1994. The spionid also reached its highest dominances in terms of biomass (40 to 90%) at this station, which was selected for the population dynamics, growth and secondary production studies. The spionid has a life span of about 3 years, and many individuals achieved sexual maturity after one year. Their growth curve is steepest during the first year of life, during which the animals grow to a length of about 180 segments. However, growth depression was observed during the ripening of the gametes in April, May and June. Secondary production was in the region of 55 to 85 g AFDW m-2 y-1. Productivity (P/B) varied considerably from generation to generation, ranging between 0 and 4.8 with an average between 1.2 and 1.6.
    Materialart: Digitale Medien
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 8 (1996), S. 29-34 
    ISSN: 1573-5176
    Schlagwort(e): Rhodophyceae ; Calliblepharis jubata ; growth ; carrageenan
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Study of the seasonal variation in the quality and content of iota carrageenan inCalliblepharis jubata from the Normandy coast of France shows that seasonal fluctuation of the environment affects the growth and chemical composition of this red alga. Growth increases during winter, when there is little synthesis of carrageenan and floridean starch is accumulated. When inorganic nitrogen content decreases, growth also decreases and stops (May to August); with high light intensity, the metabolism is oriented towards a synthesis of parietal carrageenans to the detriment of the reserve products such as floridean starch.
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 8 (1996), S. 87-103 
    ISSN: 1573-5176
    Schlagwort(e): Ascophyllum nodosum ; growth ; harvesting effects ; reproduction ; season ; survival
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Although populations ofAscophyllum nodosum are harvested commercially, little is known about the effects on demographic vital rates (growth, reproduction, survival). This study examines the effects of harvesting season and harvesting intensity on growth, reproduction and mortality of intact fronds in four size classes and in fronds truncated by the harvest. Knowledge of size-specific vital rates was used to evaluate the response of the population to harvesting. Harvesting season and harvesting intensity did not exert a significant effect on growth. Growth in plots not subject to harvesting was less than in harvested plots. No major differences in growth, reproduction and survival between intact and severed fronds emerged. The number of fronds attaining reproduction was enhanced by increased harvesting intensity and by cutting in summer. Harvesting did not seem to induce breakage, and breakage appeared higher in the uncut plots. Most harvesting treatments did not influence survivorship and survivorship was similar among all size classes. Growth rates were inversely related to sizes of fronds. Assessment of variation across size classes yielded more accurate estimates of growth rates than those of previously used methods. Accurate size class specific-growth rates will be a useful criterion when regulating intervals between harvests. Furthermore, assessment of size-specific vital rates allows identification of the frond size classes most relevant to the preservation of resources. Because of their fast growth rates and abundance, fronds in class 1, and, to a lesser extent, class 2, are responsible for most of the population regrowth after harvest. In contrast, classes 3 and 4 contribute little to recovery. This finding provides a strong basis for a harvesting strategy that targets the largest fronds.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Cytotechnology 20 (1996), S. 13-22 
    ISSN: 1573-0778
    Schlagwort(e): insect tissue culture ; cell-specific lines ; survival ; growth ; cell differentiation ; applications
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Conclusion Current methods of insect cell culture have produced a limited variety of cell types in an ever expanding list of insect cell lines. In developing midgut epithelial cell lines, we found that traditional methods in insect cell culture failed to provide healthy cells from mature tissues. Examination of mammalian cell culture literature for this particular cell type provided the insight required to successfully develop a cell-specific line (Baines et al., 1994). The potential applications for cell-specific lines from insects are numerous. This paper is a compilation of ideas that will hopefully enable other researchers to develop additional cell-specific lines.
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  • 83
    ISSN: 1573-4986
    Schlagwort(e): C-reactive protein ; pollutant ; agglutinin ; galactose binding lectin ; fish ; Labeo rohita
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Different forms of C-reactive proteins (CRPs) have been purified to electrophoretic homogeneity from the sera of Labeo rohita confined in freshwater (CRPN) and water polluted with nonlethal doses of cadmium (CRPCd) or mercury (CRPHg). CRPN[emsp4 ], CRPCd[emsp4 ], and CRPHg show remarkable differences in their electrophoretic mobility but exhibit strong immunological cross reactivity. All these CRPs exhibit variable agglutination properties with erythrocytes from diverse sources in presence of Ca+2, which could be inhibited by a variety of sugars showing specificity for galactose. Inhibition results show that the potency of galactose as an inhibitor increases about 4 fold in the process of transformation of CRPN to CRPCd and CRPHg[emsp4 ]. In case of CRPN[emsp4 ], Gal β(1→1) Gal and oNO2 phenyl β-Gal show highest inhibitory potency while oNO2-phenyl β-Gal is the most potent inhibitor for CRPCd and CRPHg but the potency of Gal β(1→1) Gal reduced drastically. 6-phosphate D-Gal and stachyose are 20 times weaker inhibitors than D-Gal for induced CRP mediated agglutination, in contrast, these sugars are only 6 times weaker for CRPN[emsp4 ]. Dissociation constants of the binding of CRPN with phosphoryl choline (PC) and galactose are about 9[emsp4 ]mM and PC binding causes a change in the α and β conformations of these CRPs.
    Materialart: Digitale Medien
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  • 84
    ISSN: 1573-5125
    Schlagwort(e): outwelling ; salt marshes ; organic matter ; transfer ; fish ; vector
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The contribution of fish communities to organic matter (OM) fluxes, especially between salt marshes and adjacent marine coastal waters are reviewed. For this a data set from the bay of Mont Saint-Michel and literature is examined and discussed. In a range of macro-tidal coasts of Europe, salt marshes are only flooded at spring tides for a short time. Many animals, including fish, then invade the salt marshes through tidal creeks. They forage there for up to a few hours and swim back to sea at ebb. Meanwhile, organic matter is exported as gut content. In the 4000 ha of salt marshes of the bay of Mont Saint-Michel mullets were responsible for the export of about 8 kg of dry weight OM ha−1 in 1996 and of roughly 12 kg in 1997. Although spatio-temporally variable, the fish communities appear to play a more or less significant role, as ‘biotic vectors’ in the nutrient fluxes between salt marshes and coastal waters.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 11 (1999), S. 551-558 
    ISSN: 1573-5176
    Schlagwort(e): Nodularia ; growth ; hepatotoxin production ; nodularin ; salinity ; irradiance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The objective of this work was to determine the influence of total dissolved solids/salinity (TDS mgL-1) on growth and biomass specific rates of nodularin (hepatotoxin) production by Nodularia spumigena 001E isolated from Lake Alexandrina, South Australia. Maximum biomass yield (dry matter, chlorophyll a and particulate organic carbon/POC) at 80 μmol photon m-2 s-1 was recorded at 3300 mg TDS L-1 and decreased at salinities above or below this value (p 〈 0.05). The maximum biomass yield (dry matter and chlorophyll a) at 30 μmol m-2 s-1 occurred at a higher salinity of 9900 mg TDS L-1. Cultures grown at 80 μmol m-2 s-1, at a TDS〉 6600 mg L-1, had significantly (p 〈 0.05) lower nodularin content (ml-1 medium) than cultures grown at the same salinities at 30 μmolm-2 s-1. The maximum total toxin concentration (mL-1 medium) occurred at 9900 and 3300 mg TDS L-1 at 30 μmol m-2 s-1and 80 μmol m-2 s-1 respectively. Toxin per unit biomass, expressed as dry matter, chlorophyll a and POC was similar for cultures grown at 30 μmol m-2 s-1 or 80 μmol m-2s-1 at salinities 〈 6600 mg TDS L-1. At salinities 〉 9900 mg TDS L-1 the toxin content per unit biomass decreased at both irradiances, however, cultures grown at 30 μmol m-2s-1 had a higher toxin content than those grown at 80 μmol m-2 s-1. The results indicate that not only do changes in irradiance and salinity directly influence growth and toxin production but that changes in irradiance affected the influence of salinity.
    Materialart: Digitale Medien
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  • 86
    ISSN: 1573-5125
    Schlagwort(e): Marenzelleria cf. viridis ; Polychaetes ; food limitation ; food selection ; growth ; gut passage time ; food quality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phytoplankton 〈 20 µm was a principal dietary component of the larvae of Marenzelleria cf. viridis. Maximum ingested particle size increased as animal size increased, reaching a maximum diameter of 80 µm for larvae with 6 to 10 setigers. The larvae started ingesting particulate matter at the 1-setiger stage and were able selectively to ingest phytoplankton and polystyrene particles of various sizes. Larvae in the 6 to 10-setiger size group did not differ from those in the 11 to 17-setiger size group in respect of size selectivity for polystyrene particles. The gut passage time for Chlorella vulgaris was ≥ 20 min. The ingestion rate was limited by food concentrations even at concentrations much higher than those encountered in the natural biotope, saturation being reached at a concentration of 28.5 times 106 cells ml-1 (117.7 mg C l-1. The low maximum filtration rate of only 1.19 µl ind.-1 h-1 indicates that the filtering capacity of the larvae is low. The larvae are still capable of food uptake at 1 °C. Further experiments demonstrated that larval growth and survival were strongly dependent on both food concentration and quality. Larval growth was food-limited under biotope conditions of the Darss–Zingst Boddens and even more so under Baltic Sea conditions. The results indicate that Marenzelleria cf. viridis is a species adapted to eutrophic conditions prevailing in brackish waters.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Aquatic ecology 32 (1998), S. 261-279 
    ISSN: 1573-5125
    Schlagwort(e): phosphorus ; fatty acid ; growth ; life history ; food limitation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Evidence suggests that marine and freshwater zooplankton generally experience food levels above subsistence values in terms of carbon. However, the quality of this food may be poor due to an insufficiency of other essential nutrients. In this review, we examine recent progress in three main areas of food quality research: (1) elemental (especially P) limitation, (2) digestion resistance, and (3) biochemical (especially fatty acids) limitation. We evaluate laboratory and field evidence in each of these areas, look at new evidence about the life history implications of the elemental limitation hypothesis, and suggest future avenues for research. From a rather large number of seemingly heterogeneous studies, a single consistent picture of food quality emerges: both P and essential fatty acids are predicted to be important dietary factors, but at different places and times. Nevertheless, despite an abundance of valuable laboratory studies, our knowledge of food quality limitation in the field is still poor.
    Materialart: Digitale Medien
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  • 88
    ISSN: 1573-5125
    Schlagwort(e): calanoid copepod ; cyclopoid copepod ; fish ; predation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We tested the outcome of predation by juvenile roach on the calanoid copepod Eudiaptomus gracilis and the similar sized cyclopoid copepod Cyclops vicinus in laboratory experiments with mixed and single-prey. When ovigerous females and adult non-ovigerous females of the calanoid copepod and the cyclopoid copepod were offered in equal numbers to the fish in the mixed-prey experiments, the cyclopoid copepods were significantly more heavily preyed upon than the calanoids. Between 14 and 16 females of the cyclopoid copepod and only between 2 and 4 calanoids had been consumed after the observation period of two hours. The single-prey experiments revealed that the conspicuousness of the calanoid vs the cyclopoid depended on sex and gravidity. Ovigerous females of the cyclopoid copepod were slightly earlier detected by the fish than ovigerous females of the calanoid, probably a result of the highly visible egg-sacs carried by the cyclopoid females. Females without eggs and males of the cyclopoid copepod were recognized later by the predator than females without eggs or males of the calanoid, probably a result of the different behaviours of the different copepod taxa. Cyclopoids frequently congregated near the aquarium bottom while calanoids were closer to the water surface where they were better visible. The calanoid copepod could better escape the fish's attacks than the cyclopoid copepod. Egg-bearing females of both the calanoid and the cyclopoid copepod could significantly better escape than non-ovigerous females or males. Probably ovigerous females react very early to water disturbances caused by the predator. Activity measurements showed that the cyclopoid copepod displayed 2 to 4 times more hops per time unit than the calanoid. Probably the high number of jerky movements displayed by the cyclopoid attracted attention of the predator and contributed to its greater vulnerability.
    Materialart: Digitale Medien
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  • 89
    ISSN: 1573-5176
    Schlagwort(e): microalgae ; temperature ; growth ; total lipids ; fatty acids ; tropical mariculture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of temperature from 10 °C to 35 °C on the growth, total lipid content, and fatty acid composition of three species of tropical marine microalgae, Isochrysis sp., Nitzschia closterium, N. paleacea (formerly frustulum), and the Tahitian Isochrysis sp. (T.ISO), was investigated. Cultures of N. closterium, Isochrysis sp. and T.ISO grew very slowly at 35 °C, while N. closterium did not grow at temperatures higher than 30 °C or lower than 20 °C. N. paleacea was low-temperature tolerant, with cells growing slowly at 10 °C. N. paleacea produced the highest percentage of lipids at 10 °C, while the other species produced maximum amounts of lipid at 20 °C. None of the species maintained high levels of polyunsaturated fatty acids (PUFAs) at high growth temperature and there was a significant inverse relationship between the percentage of PUFAs and temperature for N. paleacea. A curved relationship was found between temperature and percentage of PUFA for N. closterium and tropical Isochrysis sp., with the maximum production of PUFA at 25 °C and 20 °C, respectively. The two Nitzschia species produced higher levels of the essential fatty acid eicosapentaenoic acid [20:5(n-3)] at lower growth temperatures, but the two Isochrysis species had little change in percentage of 20:5(n-3) with temperature. Only T.ISO had the highest percentage of 22:6(n-3) at lowest growth temperature (11.4% total fatty acids at 10 °C).
    Materialart: Digitale Medien
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  • 90
    ISSN: 1573-5176
    Schlagwort(e): Lyngbya wollei ; paralytic shellfish poisons ; growth ; toxin production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Collections of Lyngbya wollei were taken from Guntersville Reservoir, Alabama, over a period of three years. Healthy filaments were isolated and transferred to agar plates of Z-8 and LM6E media. Unialgal isolates were cultured for the study of growth and paralytic shellfish poison (PSP) production. Filaments were extracted and the toxins were detected using high performance liquid chromatography (HPLC) with post column oxidation followed by fluorescence detection. HPLC profiles show that laboratory cultures of L. wollei produced decarbamoyl gonyautoxin 2 and 3, plus several other PSP like toxins whose structures are under investigation. At 26 °C and a light intensity of 11 or 22 µmol m-2 s-1 optimum production of both biomass and toxins occurred. A decrease or increase in temperature or light flux caused a reduction in dry weight or toxicity. Compared to control levels, lower PO4-P and NO3-N and higher calcium levels gave rise to higher biomass and toxicity. Lower calcium, calcium- or PO4-P deficient medium and high NO3-N or PO4-P caused a large decrease in dry weight and toxicity.
    Materialart: Digitale Medien
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  • 91
    ISSN: 1573-8590
    Schlagwort(e): China ; Qinghai ; Koko Nor ; Cyprinidae ; fish ; fishery ; recruitment ; spawning ; catch per unit effort ; management ; translocation ; saline lake ; dryland ; semi-arid ; irrigation ; conservation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geographie
    Notizen: Abstract Quinghai Hu is a large, high-altitude, saline lake in north-western China, and supports a fishery based on an endemic species of naked carp (‘snow trout’). The fish take seven years to attain maturity and a marketable weight of 300 g, and have a lifespan of 14–21 years under the present fishery regime. They seasonally migrate from the lake to spawn over the gravel beds of inflowing rivers, but these areas have been reduced by weirs and irrigation diversions and recruitment may have declined. The population may have been affected also by a 1.85-m fall in the lake level over the past 30 years, and by associated changes in salinity. The fishery was opened to large-scale exploitation in 1958. Yields declined sharply (max. 28,523 tonnes, 1960) as the larger, older fish were removed, and then more slowly (min. 2523 tonnes, 1983). Since 1987 the fish factory has been limited to an annual quota of 1200 tonnes, taken by a fleet of four pair trawlers. Another 800 tonnes are taken by licensed fishermen, mainly using gill nets, and perhaps 1000 tonnes are taken illegally. The estimated total catch in 1992 was 3000 tonnes. New trawlers introduced in 1989–90 substantially increased the factory's catch per unit effort, and in 1990 the quota was virtually filled in one month in a zone within 20 km of the factory. Although this could suggest that the stocks will be conserved if the quota is retained, at least half of the catch in 1989–92 consisted of immature individuals. Trawling operations recently were suspended following a further decline in the catch after 1992. While the new trawlers are capable of a major increase in effort, neither the changing environment, the fish stocks or the present markets favour intensified pressure. Gillnets may provide better control over the minimum size limit and may cause less damage than trawling. Other options to improve the viability and profitability of the fishery include improvements in handling, processing and marketing. Failure to develop the fishery may encourage attempts to introduce exotic fish, at some risk to survival of the local species.
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  • 92
    ISSN: 1573-8477
    Schlagwort(e): amphibian ; body size ; clonal ; genetic compatibility ; growth ; hybridogenesis ; local adaptation ; metamorphosis ; Rana esculenta ; tadpole
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Hybridogenetic species possess a hybrid genome: half is clonally inherited (hemiclonal reproduction) while the other half is obtained each generation by sexual reproduction with a parental species. We addressed the question of whether different hemiclones of the hybridogenetic water frogRana esculenta are locally adapted for genetic compatibility with their sexual parental hostRana lessonae. We artificially crossedR. esculenta females of three hemiclones (GUT1, GUT2 and GUT3) from a pond near Gütighausen, Switzerland and one hemiclone (HEL1) from near Hellberg, Switzerland each toR. lessonae males from both populations. We also created primary hybrids by crossing the sameR. lessonae males from both populations toR. ridibunda females from Poznań, Poland (POZ). Tadpoles were then reared in the laboratory at two food levels to assess their performance related to early larval growth rate, body size at metamorphosis and length of the larval period. Tadpoles from hemiclones GUT1, GUT3 and POZ had higher growth rates than those from hemiclones GUT2 and HEL1 at the low food level, but at the high food level all growth rates were higher and diverged significantly between hemiclones GUT2 and HEL1. Tadpoles from the intrapopulational crosses GUT2 × GUT and HEL1 × HEL were larger at metamorphosis than those from the interpopulational crosses GUT2 × HEL and HEL1 × GUT. A high food level increased the size at metamorphosis in all tadpoles. A high food level also decreased the days to metamorphosis and tadpoles from GUT1, GUT3 and POZ had the shortest larval period whereas those from GUT2 and HEL1 had the longest. These results indicate that the differential compatibility of clonal genomes may play an important role in hybridogenetic species successfully using locally adapted sexual genomes of parental species and that interclonal selection is likely important in determining the distribution of hemiclones among local populations.
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Water resources management 13 (1999), S. 73-84 
    ISSN: 1573-1650
    Schlagwort(e): chlorophyll ; growth ; rice crop ; spectral reflectance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geographie
    Notizen: Abstract Relations among spectral reflectance, chlorophyll ‘a’, and growth of rice plants grown on irrigated light textured soil in a semi arid region are presented here. There was a linear relation between spectral reflectance and rice plant height (r = 0.97), for band 1 (0.45–0.52 μm) reflectance values. On the other hand, in bands 2 (0.52–0.60 μm) and 3 (0.63–0.69 μm), reflectance values decreased until 70 days after planting (DAP) and then increased during the reproductive phase of the crop. The near infrared band 4 (0.76–0.90 μm) showed a maximum reflectance at 59 DAP (panicle initiation stage) and a decline in reflectance thereafter through maturity. The peak value of IR/R ratio was 16.39 at 62 DAP during the early reproductive phase; thereafter, it declines gradually with the maturity of the crop. Chlorophyll ‘a’ concentration was high during early growth (vegetative and early reproductive stages) and decreased during the flowering and maturity stages. The rice plant canopy show a high chlorophyll ‘a’ concentration at 64 and 59 DAP for sites A and B, respectively. Chlorophyll ‘a’ concentration is higher in site A plant canopies than it is in site B during the entire crop cycle. A good inverse correlation (r = 0.91) has been found between chlorophyll ‘a’ and band 1, while the IR/R ratio and the normalised difference vegetation index (NDVI) showed a relationship (r = 0.78) with the chlorophyll ‘a’ concentration during the crop cycle. Band 2, 3 and 4 radiance values show a biphasic linear relationship with chlorophyll ‘a’ concentrations, negative for early growth and positive for flowering and maturity stages. Results indicate that the period between 66 to 70 DAP is most suitable for the assessment of rice crop yield, based on chlorophyll ‘a’ concentration.
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Aquaculture international 7 (1999), S. 251-260 
    ISSN: 1573-143X
    Schlagwort(e): bacterial biofilm ; common carp (Cyprinus carpio) ; growth ; rohu (Labeo rohita) ; Tilapia (Oreochromis mossambicus)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Experiments were conducted to enhance the growth of common carp (Cyprinus carpio), rohu (Labeo rohita) and Mozambique tilapia (Oreochromis mossambicus) through use of sugarcane bagasse as substrate. Bagasse was suspended in water with or without supplementation with fertilizers. Bagasse supplemented with cattle dung and urea favoured higher zooplankton production and significantly (p 〈 0.05) increased fish growth by over 50% compared to bagasse or fertilizers on their own. This higher production of fish is attributed to bacterial biofilm promoted on the substrate which, apart from forming food for zooplankton and fish, contributed to improved water quality by lowering ammonia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Aquaculture international 7 (1999), S. 1-12 
    ISSN: 1573-143X
    Schlagwort(e): Convict cichlid (Cichlasoma nigrofasciatum ; environmental UV effects ; growth ; ultraviolet radiation ; UVA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The long term (two generations) effect an enhanced (5%) sub-lethal ultraviolet-A (320–400 nm) irradiation on growth and survival rate of a convict cichlid (Cichlasoma nigrofasciatum is presented. Two UVA irradiated populations (G1-UVA and G2-UVA) and two control populations (G1-control and G2-control) were observed from age 60 to 403 days. The UVA populations were exposed to enhanced UVA irradiation from 4 months of age (G1-UVA and from egg's state (G2-UVA). The specific growth rates (daily weight and length increase) and the condition factors of the populations were not affected by the enhanced UVA, it depended more on the population size. At the adapted temperature range (27–29 °C) the survival rate of those populations was not affected by enhanced UVA. A combined effect of enhanced UVA and increased temperature (31–32 °C) was responsible for a high mortality rate in the GI-UVA. A total of 67% of the G1-UVA population died just within a week of exposure to high temperature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    ISSN: 1573-143X
    Schlagwort(e): body composition ; dietary protein ; fecundity ; gonad maturation ; growth ; Nile tilapia (Oreochromis niloticus)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Six-week-old Nile tilapia (Oreochromis niloticus) fry with an average weight (SD) of 0.51(0.2) g were reared for 140 days on five formulated, isocaloric diets of different protein levels (25, 30, 40 and 45% by dry weight). Fish fed diets of higher protein levels (40 and 45%) showed better growth and feed conversion ratio than those on lower protein levels. Fast-growing fish matured earlier. Maturation rate was affected by the dietary protein levels. Males matured earlier than females: the first mature males were recorded when they were 14 weeks old, whereas the females matured after 18 weeks. In both sexes, mean percentage of mature fish rose with increasing dietary protein level, the percentage of mature males being higher than that of the females. Similarly, the percentage of mature fish rose with the increasing age of fish, with more than 50% males and females mature at the age of 22 and 24 weeks, respectively, the exception being the 25% protein diet fed fish, where the percentage of mature fish was below 50%. In all treatments, spawning was initiated when the fish were 22 weeks old. Smallest size at spawning of males and females was 9.2 cm (13.1 g) and 8.1 cm (8.9 g), respectively, and dietary protein levels influenced the size of fish at first maturity. For both sexes, no difference was found in the gonado-somatic index (GSI) among different treatments. Fecundity increased with increasing dietary protein levels, but significant differences were found only between 40–45% and 25–35% dietary protein levels. The relative fecundity (eggs g−1 female) was higher at the lower dietary protein levels (25–35%) than at the higher dietary protein levels (40–45%). The dietary protein levels did not have any significant influence on the size and weight of mature eggs. The chemical composition of fish and mature ovaries was significantly influenced by the dietary protein level.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    ISSN: 1573-1448
    Schlagwort(e): fish ; introductions ; management ; México ; native species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Of the 22 fish species presently inhabiting the waters of the state of Morelos, México, more than half (64%) have been introduced, mainly for fisheries and ornamental aquaculture purposes. Even though there are other significant problems such as pollution, eutrophication and drought, we found that fish introductions have caused the worst ecological impacts. These problems stem from a general lack of knowledge regarding the characteristics, importance and appropriate use and management of aquatic resources. Conservational actions are proposed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Aquaculture international 7 (1999), S. 179-187 
    ISSN: 1573-143X
    Schlagwort(e): feeding ; growth ; larvae ; micro-algae ; pearl oyster (Pinctada margaritifera L.) ; survival
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This paper reports on an experiment to determine growth and survival of blacklip pearl oyster, Pinctada margaritifera (L.), larvae fed a 1:1 mixture of Isochrysis aff. galbana clone T-ISO and Pavlova salina at six different densities (1, 2, 5, 10, 20 and 30 × 103 cells ml-1. Larval growth and survival were assessed every four days over a 20–day period. Exponential and logistic regression models were fitted to the growth and survival responses, respectively. Overall growth of larvae fed ≥5 × 103 cells ml-1 was significantly greater (p 〉 0.01) than growth of larvae reared at other algal densities. The optimal food ration for maximum larval growth was 20 × 103 cells ml-1, which resulted in larvae with antero-posterior shell length of 230 μm after 20 days. These larvae were significantly larger (p 〉 0.05) than those in all other treatments at the end of the experiment. Survival of larvae fed 0, 1 and 2 × 103 cells ml-1 was significantly lower than that of larvae in all other treatments at the end of 15 days (p 〉 0.01). Maximal survival (8%) over the 20 day period was shown by larvae fed 10 × 103 cells ml-1, while lower survival was shown by larvae fed 2 × 103 cells ml-1 (2%) and 1 × 103 cells ml-1 (0%).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Aquaculture international 7 (1999), S. 201-205 
    ISSN: 1573-143X
    Schlagwort(e): fingerlings ; growth ; light regimes ; photoperiod ; silver catfish (Rhamdia quelen) ; survival
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    ISSN: 1573-143X
    Schlagwort(e): gilthead sea bream (Sparus aurata) ; growth ; hybridization ; red porgy (Pagrus pagrus) ; survival
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Hybridization between gilthead sea bream, Sparus aurata, and red porgy, Pagrus pagrus, was undertaken and viable hybrids were produced by an artificial hormonal-induced cross. The hybrids, from the cross of female red porgy and male gilthead sea bream (Pp × Sa), survived through the yolk-sac larval stage. The hybrids produced from the cross of female gilthead sea bream and male red porgy (Sa × Pp) presented higher mortality in the larval stage (98.4%) compared to gilthead sea bream (80.0%) and red porgy (92.5%). Afterwards, the Sa × Pp hybrid was compared to the offspring of its parental species under the same rearing conditions (tanks of 500 l capacity, natural light, ambient temperature, self-feeding with commercial feed) in a 40–week experiment. In this comparative study, the Sa × Pp hybrid had intermediate mortality rate (6%), compared to gilthead sea bream (0%) and red porgy (21%). The growth profile of this hybrid resembled the slow growing phases of its parents (red porgy in warm period and gilthead sea bream in cold period). The feed conversion ratio between fish forms was not significantly different (1.54–1.84 in the Sa × Pp hybrid, 1.53–1.56 in the maternal species and 1.33–1.40 in the paternal one). The body weight variation in the Sa × Pp hybrid was quite high (31.7–37.9%), compared to that in gilthead sea bream (19.7–24.7%) and red porgy (18.0–31.3%). With respect to body coloration, the Sa × Pp hybrid was distinguishable and classified into groups of red porgy-like (55.1%), gilthead sea bream-like (40.6%), and intermediate forms (4.3%). The preliminary results of this study proved that the produced Sa × Pp hybrid had too low a performance for aquaculture use, but the interesting consequent hereditary potential could be a useful tool in fish hybridization practice.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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