Products of photosynthesis by marine phytoplankton: Chitin in TCA “protein” precipitates

Smucker, Richard A.; Dawson, R.

doi:10.1016/0022-0981(86)90101-2

Cited by 38 publications

(29 citation statements)

References 21 publications

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“…The polysaccharide fraction, on the other hand, ranges in its composition, from structural polysaccharides to nucleic acids, which are also TCA soluble (ϳ5% of cell carbon; Laws 1991). In diatoms, the protein fraction may contain as much as 33% chitin, as demonstrated for T. pseudonana (Smucker and Dawson 1986). In uniformly labeled cells, the proportion of total carbon that is labeled is the same in all biochemical fractions, and the distribution of 14 C among fractions should reflect the proportions of biochemical fractions in the cell.…”

Section: No Effect Of Levels Of Ingestion On Absorption Efficiencies-mentioning

confidence: 90%

Absorption efficiencies and biochemical fractionation of assimilated compounds in the cold water appendicularian Oikopleura vanhoeffeni

Bochdansky

Deibel

Rivkin

1999

Limnology & Oceanography

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Using 68 Ge : 14 C dual-labeling, we investigated the absorption efficiency of diatom carbon for the cold water appendicularian Oikopleura vanhoeffeni. The absorption efficiency of bulk carbon (mean ϭ 67%) was not influenced by body size or ingestion rate. For the first time for a pelagic tunicate, food and feces were fractionated into their major biochemical constituents (i.e., low-molecular-weight compounds, lipid, protein, and polysaccharide), allowing calculation of absorption efficiencies for each fraction. Low-molecular-weight compounds and proteins were preferentially absorbed over lipids and polysaccharides. However, predicted C : N ratios of the fecal pellets of O. vanhoeffeni were in the lower range of C : N ratios reported for zooplankton feces. The results are relevant for modeling biogeochemical cycles because pelagic tunicates contribute greatly to vertical particulate organic carbon flux.

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Section: No Effect Of Levels Of Ingestion On Absorption Efficiencies-mentioning

confidence: 90%

Absorption efficiencies and biochemical fractionation of assimilated compounds in the cold water appendicularian Oikopleura vanhoeffeni

Bochdansky

Deibel

Rivkin

1999

Limnology & Oceanography

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“…Subsamples from various radiolabeled chitin batches were hydrolyzed in HC1 (1 part aqueous sample:9 parts concentrated HCl) for 10 h at 80°C (Rupley 1964). Our preliminary analysis indicates that this procedure gives equal or higher recovery of glucosamine from chitin than the following procedures: 6 N HCl for 20 h at 110°C (Smucker & Dawson 1986), 3 N HCl for 4 h at 10O0C, and the H2S04 method often used for polysaccharides (Pakulski & Benner 1992). Subsamples from the hydrolyzed chitin were diluted 1:500 with deionized water and analyzed by ion exchange HPLC with pulse amperometric detection (Borch & Kirchman 1997).…”

Section: Methodsmentioning

confidence: 96%

Hydrolysis and mineralization of chitin in the Delaware Estuary

Kirchman

White²

1999

Aquat. Microb. Ecol.

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ABSTRACT. We examined various aspects of chitin degradation in order to estimate degradation rates and the contribution of chltin to supporting bacterial growth in the Delaware estuary. Hydrolysis of the chtin analog, methylumbelliferyl-N,Nf-diacetyl-chitobioside (MUF-&NAG), and mineralization of 14C-chitin varied in a conlplex pattern in the estuary and correlated only weakly at best with various indices of chitin production. Rates of MUF-diNAG hydrolysis and '"-chitin degradation were within an order of magnitude of each other, with hydrolysis rates usually exceeding chtin mineralization. Consistent with hydrolysis being greater than mineralization, we found substantial release of I4C-labeled dissolved organic matter (DOM) during degradation of the '"-chitin; DOM release was roughly equal to respiration of 14C-chitin. This DOM release could support growth of bactena not attached or otherwise associated with the chitin, but rates of DOM release and direct chitin degradation seem low relative to bacterial production During 2 cruises in July and October, chitin appeared to support 5 % or less of bacterial production, whereas during one cruise in September the percentage was about 30%. Estimates of chitin inputs into marine systems indicate that on the order of 10% of bacterial production could be supported by chitin. Although it appears low, few individual biochemicals are likely to support much more bacterial growth than chitin, with the possible exception of protein and amino acids.

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“…That leaves 1.5 to 10.5% of cellular nitrogen remaining in all other minor components such as amino sugars, AMP I ADP I ATP, histidine, tryptophan, carbamyl phosphate, cytidine triphosphate, etc. Some diatoms have been found to contain significant quantities of chitin, a polymer of the amino sugar N -acetyl-D-glucosamine, such that amino sugar nitrogen may amount to 15-20% of total cellular nitrogen in some instances (Smucker and Dawson, 1986). The compound from which these diverse biochemicals derive is glutamic acid (GLU) (Zubay, 1983).…”

Section: A Model Of the Distribution Of N Isotopes In Phytoplanktonmentioning

confidence: 99%

“…Insect chitin was also found to be depleted in 15N relative to the whole organism , as were zooplankton molts ; the latter by 3.8 to 4.6 per mil. Chitin (e.g., poly-N -acetyl-D-glucosamine) is found in certain species of phytoplankton, especially diatoms (Smucker and Dawson, 1986). Finally, nucleic acids were reported to be depleted in 15N relative to whole algal cells by about 2 per mil (Dr. Luis Cifuentes, personal communication).…”

Section: A Model Of the Distribution Of N Isotopes In Phytoplanktonmentioning

confidence: 99%

Nitrogen isotopes in chlorophyll and the origin of Eastern Mediterranean sapropels

Sachs¹

1997

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The goals of this thesis were: (1) to establish methods for the determination of nitrogen and carbon isotope ratios in marine particulate and sedimentary chlorophyll derivatives; (2) to establish chlorophyll ()15N and ol3C as proxies for the nitrogen and carbon isotopic composition of marine phytoplankton; and (3) to use chlorophyll nitrogen isotopic ratios to understand the origin of Late Quaternary Eastern Mediterranean sapropels.Techniques are presented for the determination of chlorin nitrogen and carbon isotopic ratios in marine particles and sediments with a precision greater than 0.15 per mil for both isotopes. The procedure can be performed in about 4 hours for particulate and 8 hours for sediment samples, and relies on multiple chromatographic purifications. About 20 g of a moderately organic-rich sediment are required.A technique is also presented for the determination of chlorin nitrogen and carbon isotopic ratios by isotope-ratio monitoring gas chromatography-mass spectrometry (irmGC-MS) by synthesizing bis-(tert.-butyldimethylsiloxy)Si(IV) chlorin derivatives. However, yields for the 4-step synthesis were only about 5-6% and there was a net isotopic depletion of 1.2 (± 0.3) per mil in the derivative, relative to the starting material.These techniques are then used to show that the nitrogen isotopic difference between chlorophyll and whole cells in six species of marine phytoplankton is 5.16 ± 2.40 per mil. For carbon, the isotopic difference between chlorophyll and whole cells in five species of marine phytoplankton is -0.02 ± 2.12 per mil. A model of the distribution of 15N in phytoplankton is constructed and it is demonstrated that the interspecies variability observed for the nitrogen isotopic difference between chlorophyll and whole cells can be attributed to differences in iii the partitioning of cellular nitrogen between non-protein biochemicals. In the field, where mixed assemblages of phytoplankton prevail, the isotopic difference beween chlorophyll and whole cells is expected to tend toward the average value of 5.16 per mil.Finally, the average nitrogen isotopic composition of chlorins from six Late Quaternary Eastern Mediterranean sapropels ( -5.01 + 0.38 per mil) was found to be very similar to the o15N of chlorophyll from the modem deep chlorophyll maximum ( -6.38 ± 1.80 per mil) in the Eastern Mediterranean. In addition, sapropel photoautotrophic material, calculated from the chlorin o15N, had the same isotopic composition (0.15 per mil) as both bulk sapropel sediments (-0.08 ± 0.53 per mil) and deep water nitrate (-0.05 per mil). These data suggest (a) that bottom waters were anoxic, (b) that organic matter burial efficiency was enhanced, and (c) that oligotrophic conditions similar to today persisted, in the Eastern Mediterranean during sapropel deposition. These results contradict earlier interpretations of Late Quaternary bulk sedimentary o15N in the Eastern Mediterranean. The latter concluded that the pattern of high o15N values in intercalated marl oozes and low values in ...

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Products of photosynthesis by marine phytoplankton: Chitin in TCA “protein” precipitates

Cited by 38 publications

References 21 publications

Absorption efficiencies and biochemical fractionation of assimilated compounds in the cold water appendicularian Oikopleura vanhoeffeni

Absorption efficiencies and biochemical fractionation of assimilated compounds in the cold water appendicularian Oikopleura vanhoeffeni

Hydrolysis and mineralization of chitin in the Delaware Estuary

Nitrogen isotopes in chlorophyll and the origin of Eastern Mediterranean sapropels

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