ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Collection
Publisher
Years
  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intertidal macroalgae may spend a significant part of their lives in air. During photosynthesis in air, they encounter much lower concentrations of inorganic carbon than in seawater. Because they accumulate inorganic carbon from seawater, we investigated whether they similarly accumulate it from air. We measured photosynthesis in the intertidal species Fucus vesiculosus L. during 1990 and 1991 with a gas-phase O2 electrode or CO2-exchange apparatus in air and with a liquid-phase O2 electrode in seawater. Maximum rates were rapid and similar in air and seawater regardless of the method. Tissue from seawater could carry on photosynthesis in CO2-free air, indicating that carbon was stored in the tissue. After 2 h, this store was depleted and photosynthesis ceased. Supplying CO2 in air replenished the store. Under identical conditions, terrestrial C3 and C4 species showed no evidence of this store, but a CAM (crassulacean acid metabolism) species did. However, in contrast to the CAM behavior, F. vesiculosus did not store CO2 significantly in the dark. We found a small acid-releasable pool of carbon in the tissue that disappeared as photosynthesis depleted the carbon store. However, the pool was too small to account for the total carbon stored. While CO2 was being acquired or released from the store in the light, photosynthesis was not inhibited by 21% O2. These results indicate that there are two parallel paths for the supply of CO2 to photosynthesis. The first depends on inorganic carbon in seawater or in air and supports rapid photosynthesis. The second involves CO2 slowly released from an organic intermediate. The release protects CO2 fixation from the inhibitory effects of 21% O2. Photosynthesis in F. vesiculosus thus appears to be C3-like in its rapid fixation of CO2 from a small inorganic pool into phosphoglycerate. However, it is C4-like in its pre-fixation of carbon in an organic pool in the light, and is CAM-like in its ability to slowly use this pool as a sole source of CO2. The organic pool may serve to protect photosynthetic CO2 fixation against the inhibitory effects of O2 in air and in the boundary layer in seawater.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mechanisms of salinity acclimation in the euryhaline freshwater living teleost, Etroplus maculatus (Bleeker), were studied. Brain water content decreased steadily with increasing salinity of the medium. Liver and muscle water content increased initially in 30% sea-water but in higher salinities decreased markedly, approximating control levels. Osmotic pressure of tissue fluid increased by 33% from 0.45% NaCl equivalent in freshwater to 0.60% NaCl equivalent in 100% sea-water. K and Mg decreased in dilute saline media but in 100% sea-water increased markedly approximating control levels; this is especially so in regard to Mg. Na decreased steadily and Ca increased with increasing salinity. Cl increased in 60% sea-water but decreased in 100% sea-water; however, its concentration in 100% sea-water exceeded that in freshwater. Free amíno acids increased by 11% in 30% sea-water but decreased in 60% and 100% sea-water, such that their concentration was lower by 28% in 60% sea-water and by 34% in 100% sea-water relative to the control level. Ascorbic acid decreased by 37% in 30% sea-water but in 60% and 100% sea-water increased steadily approximating the control level. The significance of these changes in the physiology of salinity acclimation is discussed and a correlation suggested between acclimation to salinity and to high temperature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 1 (1967), S. 113-117 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous authors have suggested that there exist close correlations between the topography of the brain and the mode of life in isopods. This paper describes and illustrates the central nervous system of Thenus orientalis (family: Scyllaridae) and evaluates the findings in evolutionary terms. Considering the shortening of the connectives and the fusion of ganglia in the thoracic region of the ventral nerve cord, T. orientalis shows more pronounced marks of specialization than highly evolved isopods; in regard to the topographical displacement of the anatomical units of the brain, it occupies an intermediate position between the primitive Mysidacea and the advanced Isopoda.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 1 (1967), S. 134-135 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The antigenic composition of the sperm surface in Paracentrotus lividus Lam. and Sphaerechinus granularis Lam. was studied using the sperm agglutination test with homologous and heterologous antisera. The results indicated that sperm of both species have at least one antigenic determinant located on their surface and shared by both species. In addition, Paracentrotus sperm bear at least one species specific determinant on their surface. The existence of antigenic determinants common to gametes of both species was demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution of pelagic larvae, juvenile and epitoquous stages of shallow shelf bottom invertebrates, in the plankton of the Norwegian and Barents Seas is largely determined by the distribution of the respective parental forms. The various currents influence the distribution only secondarily and to a rather limited extent. Most larvae remain in the water masses above the zones inhabited by their parents. Thus their large scale distribution in the plankton is determined primarily by the ecological and zoogeographical patierns of distribution of the parental life cycle stages. Such dependence of larval distributions on the distribution of adults in the benthos is assumed to represent a general pattern in all shallow regions of the world oceans.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The plasmaprotein of a specimen of Grampus griseus G Cuvier, captured in the Western Mediterranean, is studied for the first time and the data obtained are compared with data previously determined by the same method (microelectrophoresis on cellulose acetate gel) for Stenella, Delphinus and Phocaena. Some hematochemical values related to glycemia, azotemia and cholesterolemia (total and fractional) are also given and discussed, together with data on glutamic oxalacetic and glutamic pyruvic transaminases; special reference is made to the theory of Cornelius (1963) on hepatic glutamic pyruvic transaminase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 1 (1968), S. 185-190 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung 1. In einer früheren Arbeit (Gessner und Hammer, 1960) wurde an Versuchen mit Ulva und Posidonia —ausgeführt an der Biologischen Station Villefranche (Südfrankreich) — gezeigt, daß die Photosynthese nach Überführung aus Meerwasser in Leitungswasser sofort absinkt und hier mitunter negative Werte aufweist. Rückführung in Meerwasser führt in der Regel nahezu zur sofortigen Herstellung der Anfangsleistung. Jedem Verdünnungsgrad zwischen Meerwasser und Leitungswasser war eine bestimmte photosynthetische Leistung zugeordnet. 2. Das gleiche Verhalten konnte in dem darauffolgenden Jahr an marinen Pflanzen des Karibischen Meeres nachgewiesen werden. Diese Untersuchungen zeigten auch, daß der Leistungsabfall bei Überführung in destilliertes Wasser weitaus größer war, als in einer 1/1000 Mol Bicarbonatlösung. 3. Schon damals (1960/61) tauchte daher die Vermutung auf, daß in manchen Fällen der Salzgehalt über das CO2-Bicarbonatsystem die Photosynthese beeinflußt. Beweise dafür konnten 1967 in Rovinj erbracht werden, wo das Leitungswasser infolge seiner hohen Alkalinität einen mehrfach höheren CO2 und HCO3-Gehalt hat, als das Leitungswasser in Villefranche. Dementsprechend zeigten Ulva und Posidonia bei Überführung in Leitungswasser gegenüber dem Meerwasser sogar eine erhebliche Leistungssteigerung und verhalten sich somit gegensätzlich zu den in Villefranche ausgeführten Versuchen. 4. Bei allen kurzfristigen Untersuchungen über den Einfluß des Salzgehaltes auf die Photosynthese ist das C-Angebot als entscheidender Faktor zu berücksichtigen. Für das Brackwasser lassen sich jedoch keine allgemein gültigen Regeln aufstellen, da dieses — ent sprechend der verschiedenen Alkalinität des Süßwasseranteils — ein höheres oder geringeres C-Angebot gegenüber dem Meerwasser aufweist. Da sich hier auch das Verhältnis von CO2 und HCO3 verschieben kann und die marinen Pflanzen andererseits diese beiden Komponenten verschieden gut auswerten können, erhöht sich erneut die Mannigfaltigkeit der Reaktionsformen. 5. Darüber hinaus übt natürlich der Salzgehalt —vornehmlich über den osmotischen Wert — eine direkte Wirkung auf die Photosyntheserate aus, da durch Exosmose das Gefüge des Zellinneren in mannigfaltiger Weise beeinflußt wird. Oft wird bereits nach kurzfristigem Aufenthalt in Leitungswasser oder destilliertem Wasser die normale photosynthetische Leistung im Meerwasser nicht mehr erreicht. Solche direkten Wirkungen des Salzgehaltes müssen sich natürlich besonders im langfristigen Versuch zeigen.
    Notes: Abstract Marine plants — phanerogams as well as algae — show a proportional decrease of photosynthetic rate, when the salinity is lowered by dilution with distilled water. Using natural water instead of distilled water, it is absolutely indispensable to take into consideration the carbon supply. Normally, the photosynthetic rate decreases in freshwater with low alcalinity, in comparison to marine water. On the other hand, using water with high contents of bicarbonates, assimilation rate is higher than in marine water. These results show that salinity may indirectly affect photosynthesis due to differences in carbon supply. The direct influence is caused by exosmosis in hypotonic media and is irreversible. — The author cannot but agree with the statement by Ogata and Matsui (1965): “It may generally be said that the changes in salinity, osmotic pressure, pH, and also carbon dioxide supply, particularly in natural sea-water, are rather inseparably associated.”
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé 1. Le cycle de Krebs et la chaîne des cytochromes sont peu efficaces chez la majorité des espèces, exceptés les Céphalopodes (muscles de l'entonnoir et du manteau, animés de mouvements rythmiques). 2. La voie des pentoses est présente dans tous les muscles et en rapport avec les synthèses de lipides et de mucopolysaccharides. 3. La teneur en hexosamines liés aux protéines diminue lorsque l'activité cytochrome oxydase croît, o'est-à-dire lorsque ces muscles jouent un rôle plus grand dans la motricité de l'animal (Octopus) que dans sa fixation au substrat (Acanthochiton).
    Notes: Abstract The results of this investigation seem to confirm the hypothesis of a biochemical adaptation of smooth muscles of molluses to the degree of their activity and tissue vascularisation. A correlation exists between the activity of the muscle and its hexosamine and cytochrome oxydase contents; in general, low cytochrome oxydase activity is correlated to high hexosamine content. In all species studied, the importance of the hexosemonophosphate shunt is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Echinoids, notably Lytechinus variegatus and Tripneustes ventricosus, and other reef flat animals (brachyuran crabs, chitons and ophiuroids) were observed to suffer heavy mortality in Puerto Rico during extreme, midday low water stands which occur in the spring and summer seasons. Death often resulted from prolonged exposure to intense heating (up to 40°C) in pools and slowly circulating bodies of water over periods of clear and calm weather; desiccation caused death in echinoids which subsequently floated away from the reef with the rising tide. The tolerance limits to exsiccation and high thermal stress were determined and found to lie within the lethal range realized on the reef. Unprotected Tripneustes may also be killed from exposure to the shorter radiations of sunlight. Severe mortalities were observed in populations of Lytechinus (64%) and Tripneustes (86%) located at a shallow depth toward the lee side of the reef. Less affected were the echinoids Echinometra lucunter, Diadema antillarum and Brissus unicolor. Similar, tide-related echinoid kills are expected to occur at other localities in the Caribbean region.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 1 (1967), S. 60-64 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Comparative studies on feeding, digestion, absorption and conversion have been made in the fish Megalops cyprinoides fed with mosquito fish, Gambusia affinis, and prawn, Metapenaeus monoceros, (Pandian, 1967). Feeding as well as digestion rates are faster in individuals fed with Gambusia than in those fed with prawn. The extent of the differences in food intake is more pronounced in smaller individuals than in larger ones. The prawn exoskeleton prolongs the duration of digestion and thus further reduces rate and amount of food intake. Changes in food quality do not affect absorption efficiency. Both, rate and efficiency of food conversion, are higher in M. cyprinoides fed with Gambusia than with prawn.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...