Correlation between oxygen utilization and electron transport activity in marine phytoplankton

Kenner, R. A.; Ahmed, S. I.

doi:10.1007/bf00390717

Cited by 68 publications

(27 citation statements)

References 6 publications

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“…This ratio falls within the ETSA/R range of 5.6 to 9.4 reported for 10 species of phytoplankton (Kenner & Ahmed 1975b), and is higher than those reported for zooplankton, which range between 1.0 and 2.0 (Hernández- Leó & Gómez 1996). The high ETSA/R ratio of phytoplankton suggests that photosynthetic organisms do not exploit their full respiratory potential in the dark, due to substrate limitation (Peñuelas et al 1988).…”

Section: Respiration and Etsa Of Isolated Zooxanthellaesupporting

confidence: 66%

“…Consequently, we can hypothesize that the amount of ETS in corals is adapted to the amount of substrate 136 Agostini et al: Coral ETSA and calcification available and therefore to the zooxanthellae density. The ETSAs measured for micro-picoplankton in the open ocean have been found to be correlated with the amount of organic carbon available for respiration (Kenner & Ahmed 1975b, Savenkoff et al 1995b, Lefevre et al 1996, Arístegui et al 2005) and deepocean ETSAs can be equated with new production in surface waters (Packard et al 1988). Similarly, in the case of sym biotic corals, the host ETSA may be equivalent to the rate of carbon translocation from the zooxanthellae to the host.…”

Section: Etsa/r Ratio and Host Respirationmentioning

confidence: 99%

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Respiratory electron transport system activity in symbiotic corals and its link to calcification

Agostini¹,

Fujimura²,

Fujita³

et al. 2013

Aquat. Biol.

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Scleractinian corals host photosynthetic endosymbionts, making direct measurement of the host respiration rate via incubation methods based on O 2 consumption impossible. We tested the use of the respiratory electron transport system activity (ETSA) for measuring host potential respiration. The applied method, modified from a previous study, is based on the reduction of (4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) to formazan. After the development of a protocol suitable for corals, the method was tested on 5 different species. Metabolism, including photosynthesis, dark respiration and light and dark calcification, was measured through incubation. Host and zooxanthellae fractions were separated and their ETSAs, protein contents and zooxanthellae densities were measured. Mean ETSA/dark respiration (ETSA/R) ratios for host corals ranged from 1.7 ± 0.2 to 3.5 ± 0.6, while ratios for zooxanthellae ranged from 3.7 to 7.8. The high ratios observed for zooxanthellae indicate that their respiration may be 5 times higher under light conditions than in the dark. Considering the obtained ratios, host respiration in light could increase at most by a factor of 3.5 compared with dark respiration rates. Ratios close to 1 were found for some specimens, which suggests that higher respiration rates under light compared with dark conditions are not possible. Therefore, increased respiration in light cannot explain the observed enhancement of calcification under light conditions. ETSA was correlated with zooxanthellae density, suggesting adaptation of the levels of host ETS enzymes to the amount of translocated photosynthetates under optimal conditions. Estimated dark host respiration was correlated with photosynthesis, which suggests that it is determined mainly by the amount of energy available but also the amount of electron transport system enzymes. This constrains the amount of ATP available for calcification. Hence, we propose a mechanism by which respiration limits the calcification rate. KEY WORDS: Electron transport system · ETS · Respiration · Calcification · Symbiotic coralsResale or republication not permitted without written consent of the publisher Aquat Biol 18: 125-139, 2013 host photosymbionts known as zooxanthellae, which is the name given to a wide array of different algae of the genus Symbiodinium.The biochemical methods proposed for conducting respiratory measurements include the quantification of respiratory electron transport system activity (ETSA) (Packard 1971), which was later modified by Owens & King (1975). This method measures the activities of the enzymes that constitute the electron transport system (ETS) at saturated substrate concentrations. Therefore, ETSA represents the potential respiratory rate and has been used to estimate oxygen consumption in various environments and community assemblages, including sediment meiofauna (Olanczukneyman & Vosjan 1977, Broberg 1985, Relexans 1996a, plankton (Kenner & Ahmed 1975a, Owens & King 1975, Packard et al. 1975, Bams...

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Section: Respiration and Etsa Of Isolated Zooxanthellaesupporting

confidence: 66%

Section: Etsa/r Ratio and Host Respirationmentioning

confidence: 99%

Respiratory electron transport system activity in symbiotic corals and its link to calcification

Agostini¹,

Fujimura²,

Fujita³

et al. 2013

Aquat. Biol.

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“…Parallel samples were filtered through GF/C Whatman filters to remove essentially all of the phytoplankton. The filtrates were assayed for respiration rate, measured by O 2 uptake in dark bottles with a high precision Winkler method and by the 'electron transport system activity' (ETS) method of Packard (1971), as modified by Kenner & Ahmed (1975). Peptidase, β-glucosidase and lipase enzyme activities were also determined in these samples using respectively the fluorogenic substrate analogs MCA-leucine, MUF-glucose and MUF-oleate (Hoppe 1993).…”

Section: Methodsmentioning

confidence: 99%

Metabolically active bacteria in Lake Kinneret

Berman¹,

Kaplan²,

Chava³

et al. 2001

Aquat. Microb. Ecol.

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“…Activité déshydrogénasique Cette activité est évaluée en suivant la réduction du TTC (Triphényl Tétrazolium Chloride) au niveau de la chaîne respiratoire en monoformazan qui absorbe à 520 nm (Zimmerman.1975). Kenner & Ahmed (1975) ont montré qu'il existe une bonne corrélation entre l'activité des déshydrogénases et la consommation d'oxygène par les micro-organismes.…”

Section: Choix Récolte Et Traitement Du Matériel Végétalunclassified

Variation de l'activité des micro-organismes au cours de la décomposition des feuilles deSalix pedicellatadans le réseau de la Basse Moulouya, Maroc oriental

Chergui

Legssyer

1995

Ann. Limnol. - Int. J. Lim.

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En dépit de l'importance des micro-organismes dans le processus de décomposition de la matière organique dans le milieu aquatique, les études sur leur dynamique et leur mode d'action restent restreintes.Dans cette étude nous essayons de quantifier l'activité des micro-organismes en suivant la dynamique des cellulases, des hydrolases et des déshydrogénases, groupes d'enzymes intervenant dans la transformation de la matière organique de structure complexe en substances simples. Les résultats montrent une liaison entre la vitesse de décomposition des feuilles du saule et l'activité enzymatique des micro-organismes associés. Les fortes valeurs de l'activité des micro-organismes s'observent sur les feuilles incubées dans le site amont du Zeghzel où le processus de décomposition est plus rapide.Le séchage des feuilles, avant leur immersion dans l'eau, influence profondément l'activité hydrolytique et cellulolytique, -alors que l'activité des oxydo-réductases reste indifférente à l'état du matériel en décomposition. L'activité déshydrogénasique est importante au printemps, s'accentue en été et s'atténue en automne et en hiver. L'activité cellulolytique est très prononcée pendant la saison automnale. Elle est plus élevée dans la Branche Sud-Ouest que dans les deux autres stations étudiées. Malgré l'existence de variations spatiale (entre les trois sites) et temporelle (entre les saisons) les dynamiques des trois groupes enzymatiques semblent très dépendantes les unes des autres. Variation in the activity of the micro-organisms during the decay of the leaf litter of Salix pedicellata in the Lower Moulaya system, eastern MoroccoKeywords : fresh leaves, déshydrogénases, cellulases, hydrolases, season, Morocco.Despite the importance of micro-organisms in the decay of organic matter in aquatic ecosystems, the study of their dynamics and activity remains still very reduced. In this paper, we try to quantify the activity of the micro-organisms with enzymatic methods. We describe hydrolase, deshydrogenase and cellulase dynamics during the processing of Salix pedicellata leaf litter in the Lower Moulouya system. The results show a correlation between the rate of decomposition and the enzymatic activity of linked micro-organisms. Evidently, the high values of the micro-organisms activity were detected in the Southwestern Branch characterized by a quick rate of decay.The drying of leaves influences deeply the hydrolase and cellulase dynamics, when the desydrogenase activity remains unaffected by decay of the leaves. This activity increase during spring, peaked during summer, rather decreased during cool season (autumn and winter). The cellulase activity rose its maximum in the Southwestern Branch in autumn. Despite the spatio-temporal variation in their dynamics, the three enzymatic groups evolved dependency.

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Correlation between oxygen utilization and electron transport activity in marine phytoplankton

Cited by 68 publications

References 6 publications

Respiratory electron transport system activity in symbiotic corals and its link to calcification

Respiratory electron transport system activity in symbiotic corals and its link to calcification

Metabolically active bacteria in Lake Kinneret

Variation de l'activité des micro-organismes au cours de la décomposition des feuilles deSalix pedicellatadans le réseau de la Basse Moulouya, Maroc oriental

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