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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Microbial ecology 15 (1988), S. 311-321 
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stenothermic cold adaptation was a predominant growth characteristic among biopolymer degrading bacteria from Antarctic shelf sediments. Psychrophilic decomposers of protein (gelatin), chitin, and cellulose accounted for up to 84, 93, and 68%, respectively, of 0°C-isolates from selected compartments of the sediments. Macroinvertebrates were recognized as a selective pressure on these fast-growing (zymogenous) psychrophiles. Psychrophilic properties of growth and biopolymer degradation coincided most in the case of proteolytic isolates. On the other hand, the majority of psychrophilic chitin- and cellulose-decomposers showed less efficient biopolymer degradation at environmental temperatures (0°C). Temperature optima of the activities of pertinent depolymerizing enzymes (e.g., scleroprotease) exceeded by far the temperature optima for growth (between 4 and 12°C). Therefore, it appears likely that enhanced rates of enzyme synthesis at low temperatures play a crucial role for the degradation of detrital organic matter in this permanently cold environment.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A total of 103 strains of estuarine, Chitinoclastic bacteria isolated from water, and sediment samples collected from the upper Chesapeake Bay, including 17 freshwater and 11 seawater isolates, were subjected to numerical taxonomy analysis. The isolates included 44 yellow-orange pigmented strains classified asCytophaga-like bacteria (CLB) of theCytophagaceae. Salt requirement of the strains ranged from tolerance to ≤1% NaCl to an absolute requirement for NaCl, with 1% NaCl satisfying this requirement. The largest phenon consisted of facultatively anaerobic, oligo-nitrophilic, and flexirubin pigment-producing freshwater and estuarine isolates, and included reference strains of bothCytophaga johnsonae Stanier andCytophaga aquatilis Strohl and Tait. Other phena, containing a smaller number of strains, comprised marine and estuarine isolates which did not produce flexirubin pigments, and required organic nitrogen for growth and for production of chitinolytic enzymes. Salt-requiring, flexirubin pigment-producing, chitin-degrading strains were, on occasion, isolated from estuarine samples and represented phena found in estuaries. Most of theCytophaga isolates, as well as chitin-degrading species not of the genusCytophaga that were isolated from Chesapeake Bay, clustered in phena representing previously described species of aerobic, zymogenic, chitinoclastic bacteria. When the frequency of occurrence of features related to environmental parameters, viz., pH, salinity, temperature range of growth, and growth on media lacking organic nitrogen, was calculated, ecological groupings of strains in the 2 major phena of CLB could be distinguished among the estuarine, chitin-degrading bacteria.
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  • 3
    ISSN: 1432-072X
    Keywords: Lipoamino acid ; Glycine lipid ; Ornithine lipid ; Sulfonolipid ; Chemosystematic marker ; Cytophaga spp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cytophaga johnsonae Stanier strain C21 (C. johnsonae C21) contains phosphatidylethanolamine (PE), an unusual glycine-containing lipid (glycine lipid), and two kinds of unidentified lipid as major lipid components. One of the latter lipids was identified by chemical and physicochemical methods as iso-3-hydroxy fatty acid, α-amide linked to ornithine and esterified to iso-nonhydroxy fatty acid (ornithine lipid). The other lipid was identified as a sulfonolipid by a tracer experiment using 35S. PE, glycine lipid and sulfonolipid were found in all seven species of Cytophage examined, namely, C. huchinsonii, C. heparina, C. johnsonae C21, C. aquatilis, and three unidentified species of Cytophaga. However, ornithine lipid was found only in the latter five species. By contrast, a serine-containing lipid, which is a specific lipid component of Flavobacterium species, was not found in any species of Cytophaga examined. The possible use and significance of amino acid-containing lipids and sulfonolipids as chemosystematic markers of the Cytophaga species are discussed.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1574-6941
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Nitrogen is the single most limiting factor for rice production. Detailed knowledge on nitrogen dynamics in rice fields is therefore of major importance for developing sustainable rice production. A combination of state-of-the-art microsensor, stable isotope tracer, and molecular techniques was used to evaluate coupled nitrification–denitrification potentials and community structure of ammonia-oxidizing bacteria in a high yield irrigated rice cropping system in the Philippines, without the use of microcosm incubations. The multiple approaches showed a high degree of concordance among methods and thereby clarified the investigated processes. Numbers and potential activity of ammonia-oxidizing bacteria in the system reflected the availability of substrate in three defined soil factions with a ranking of: surface soil 〉 rhizosphere 〉 bulk soil. No nitrification activity was measured between spit applications of N fertilizer. However, nitrification was induced upon nitrogen amendment in intact soil cores. Despite induction by nitrogen amendment, the loss of nitrogen through coupled nitrification–denitrification was less than 10% of the plant nitrogen uptake. Denaturant gradient gel electrophoresis of amoA fragments revealed no differences in diversity profiles between the soil fractions, and phylogenetic analysis, based on amoA genes retrieved from the rice paddy soil, identified a set of mutually very similar sequences related to Nitrosomonas nitrosa.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Le dosage de la sérotonine dans le sang prélevé en des points précis du système veineux abdominal grâce au cathétérisme sélectif a été étudié par les auteurs au plan du diagnostic et de la localisation de la tumeur carcinoide. Le taux de la sérotonine a été déterminé par une technique enzymatique portant sur une fraction plasmatique plaquettaire particulière (P.P.P.P.). Chez 5 sujets normaux, la concentration de la sérotonine dans des échantillons sanguins prélevés au niveau de l'artère coeliaque, de la veine hépatique ?, des veines pancréatiques et de différentes veines de l'appareil digestif s'est située entre 1,2,5, 4 ng/ml. Chez 10 malades qui présentaient des tumeurs carcinoïdes cette concentration dans le sang des veines drainant les tumeurs étaient nettement élevées et variait entre 10 ng/ml et 80 ng/ml. Chez ces mêmes malades 5 dosages de 5 H.I.A.A. urinaire faussement négatif ont été constatés ainsi que 2 scintigraphies hépatiques faussement négatives et 2 angiographies d'interprétation incertaine. La méthode étudiée se présente donc comme un complément utile des autres méthodes d'explorations permettant de porter le diagnostic de tumeur carcinoïde, de déterminer son siège et de suivre l'évolution des malades porteur de cette lésion.
    Abstract: Abstracto Se realizó la evaluación del cateterismo selectivo de venas abdominales en relación a su uso en el diagnóstico, localización y caracterización de carcinoides. La serotonina fue determinada en una fracción de plasma pobre en plaquetas (PPP) por un procedimiento enzimático. La concentración de serotonina en PPP en la arteria celiaca, la vena hepática y en diferentes venas intestinales y pancreáticas osciló entre 1.2–5.4 ng/ml. En 10 pacientes con tumores carcinoides la concentración de serotonina en las venas que drenaban el tumor se encontró notoriamente elevada y varió desde 10 mg/ml hasta 88 mg/ml PPP. Los niveles de 5-HIAA en orina fueron negativos falsos en 4 casos, el centelleoescanograma del hígado fue negativo falso en 3 casos y el angiograma fue no conclusivo en 2 casos. La técnica de la determinación de serotinina en el plasma en combinación con el cateterismo selectivo es un complemento útil de otras técnicas investigativas en el diagnóstico, localización y seguimiento de pacientes con tumores carcinoides.
    Notes: Abstract Selective abdominal vein catheterization with blood sampling for serotonin determination was evaluated regarding its use in the diagnosis, location, and characterization of carcinoids. Serotonin was determined in a platelet-poor plasma fraction (PPP) by an enzymatic procedure. In 5 normal subjects the concentration of serotonin in PPP in the celiac artery, the hepatic vein, and different intestinal and pancreatic veins ranged from 1.2 to 5.4 ng/ ml. In 10 patients with carcinoid tumors, the concentration of serotonin in tumor-draining veins was clearly elevated and ranged from 10 ng/ml to 88 ng/ml PPP. 5-HIAA urine levels were false-negative in 4 cases, liver scintiscan was false-negative in 3 cases, and the angiograms were not conclusive in 2 cases. The technique with plasma serotonin determination in combination with selective catheterization is a useful complement to other investigative techniques in the diagnosis, location, and follow-up of patients with carcinoid tumors.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 38 (1971), S. 377-394 
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung In einigen eutrophen Seen sowie in axenischen Blaualgen-Kulturen wurden die Katalysebedingungen für die hydrolytische Spaltung von Phosphorverbindungen untersucht. Der hitzestabile Anteil filtrierter Wasserproben besa\gB zwar niedrige, jedoch deutlich pH-abhängige Aktivitäten von Phosphomonoesterasen (PME;EC.3.1.3), wenn p-Nitrophenylphosphat als unspezifisches Substrat diente. In 3 verschiedenen See-Biotopen korrespondierten circadiane Schwankungen der PME mit den Konzentrationen der gelösten Phosphorverbindungen und den Bakterienkeimzahlen. In Vertikalprofllen des Plu\gB-Sees unterlagen die PME-Aktivitäten beträchtlichen jahreszeitlichen Schwankungen. Hier schienen eher die kinetischen Parameter (Michaelis-Konstanten )als die reinen Aktivitäten mit den Phosphatgehalten im Biotop korreliert. Diese Ergebnisse stimmten grö\gBtenteils mit einigen physiologischen Regulationsmechanismen der PME überein, die in Blaualgen-Kulturen unter dem Einflu\gB definierter Au\gBenmilieufaktoren beobachtet wurden konnten. Ein axenischer Stamm von Anacystis nidulans vermochte verschiedene hydrolysierbare Phosphorverbindungen bis zu einem gewissen Grade zu verwerten. Aktivitäten und kinetische Parameter (km; Vmax) der PME wurden in Kulturfiltraten und Zellaufschlüssen untersucht. Die so ermittelte Effektivität der Dephosphorylierung stieg, wenn die Zellen in P-limitierten Kulturmedien wuchsen, oder, wenn das Wachstum durch andere Au\gBenfaktoren verlangsamt war.
    Notes: Summary Catalytic conditions of the hydrolysis of phosphorus compounds have been examined in some eutrophic lakes as well as in axenic cultures of blue-green algae. The heat labile part of filtered samples of lakewater was revealing low, but distinctively pH-dependent activities of phosphomonoesterases (PME, E.C.3.1.3), when p-nitrophenylphosphate was used as a non-specific substrate. In 3 different lake biotops circadian fluctuations of PME were found to be corresponding with the content of dissolved phosphorus compounds and the counts of saprophytic bacteria. In vertical profiles of Lake Pluss activities of PME were subjected to considerable annual fluctuations. Here rather the kinetic parameters (Michaelis-Menten-constants) than the mere activities appeared to be correlated with the environmental concentrations of phosphate. These results corresponded in large part with some physiological regulations of phosphomonoesterase activities which could be observed in cultures of blue-green algae in relation to some defined environmental factors. An axenic strain of Anacystis nidulans was able to utilize different hydrolyzable phosphorus compounds up to a certain degree. In both the culture filtrates and the disintegrated cells the activities and the kinetic parameters (km; Vmax) were tested. The efficiency of dephosphorylation estimated by this means increased, when cells were grown in culture media limited by the source of P, or when growth had been retarded by other environmental factors.
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