Hydrolysis and mineralization of chitin in the Delaware Estuary

Kirchman, David L.; White, Jacques R.

doi:10.3354/ame018187

Cited by 68 publications

(52 citation statements)

References 27 publications

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“…The involvement of Flavobacteria in the hydrolysis of macromolecules, such as chitin and cellulose, has been suggested before (Kirchman 2002). Even if the majority of planktonic Flavobacteria taking up NAG and diNAG were not ELFH97-NAG positive, the occurrence of this phyla in dense clusters on chitin particles implies that they were actively contributing to the hydrolysis of chitin.…”

Section: Discussionmentioning

confidence: 93%

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Uncoupling of chitinase activity and uptake of hydrolysis products in freshwater bacterioplankton

Beier

Bertilsson

2011

Limnology & Oceanography

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We investigated to what extent chitinolytic bacteria subsidize bacterial populations that do not produce chitinolytic enzymes but still use the products of chitin hydrolysis. Applying single-cell techniques to untreated and chitin-enriched lake water, we show that the number of planktonic cells taking up chitin hydrolysis products by far exceeds the number of cells expressing chitinases. Flavobacteria, Actinobacteria, and specifically members of the abundant and ubiquitous freshwater Ac1 cluster of the Actinobacteria, increased in abundance and were enriched in response to the chitin amendment. Flavobacteria were frequently observed in dense clusters on chitin particles, suggesting that they are actively involved in the hydrolysis and solubilization of chitin. In contrast, Actinobacteria were exclusively planktonic. We propose that planktonic Actinobacteria contain commensals specialized in the uptake of small hydrolysis products without expressing or possibly even possessing the machinery for chitin hydrolysis. More research is needed to assess the importance of such ''cheater'' substrate acquisition strategies in the turnover and degradation of polymeric organic matter in aquatic ecosystems.

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Section: Discussionmentioning

confidence: 93%

“…More specifically, enzyme-mediated release of labile DOC has also been demonstrated for chitin particles (Kirchman and White 1999). Chitin is one of the most abundant biopolymers in aquatic systems.…”

mentioning

confidence: 99%

Uncoupling of chitinase activity and uptake of hydrolysis products in freshwater bacterioplankton

Beier

Bertilsson

2011

Limnology & Oceanography

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Section: Discussionmentioning

confidence: 99%

“…A host of different chitin-hydrolyzing bacteria is present in the marine environment (Osawa & Koga 1995, Kirchman & White 1999. The peritrophic membrane surrounding fecal pellets consists of chitin, and its breakdown appears to be facilitated by high hydrolytic activity.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, chitin may play an important role in bacterial production associated with copepod fecal pellets. Certainly, hydrolysis of chitin has been shown to support a substantial part of estuarine bacterial production (Kirchman & White 1999).Production of attached bacteria did not result in increased bacterial abundances on the fecal pellets. Since bacteria show a range of different strategies for reversible attachment and release from surfaces (Marshall 1996), the uncoupling of bacterial production and abundance could be attributable to newly produced bacterial cells being released from the fecal pellets.…”

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confidence: 91%

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Fate of organic carbon released from decomposing copepod fecal pellets in relation to bacterial production and ectoenzymatic activity

Thor

Dam²,

Rogers³

2003

Aquat. Microb. Ecol.

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Fecal pellets were produced by Acartia tonsa fed 14 C-labeled diatom, cryptophyte, and dinoflagellate diets, and were incubated in 1.2 µm-filtered Long Island Sound seawater. Based on the 14 C label, the decrease in fpOC (fecal pellet organic carbon), the release and fate of dissolved organic carbon (DOC) and particulate organic carbon (POC), as well as bacterial production and enzymatic activity, were followed over a 96 h period. fpOC decreased by 9, 14, and 19% d -1 in diatom, cryptophyte, and dinoflagellate pellets, respectively. There was a fast, possibly passive, leakage of DOC from pellets from all 3 diets within a few hours after egestion, which may not have been utilized by attached bacteria. Bacterial production rates were 17, 12, and 31 pg C pellet -1 h -1, on diatom, cryptophyte, and dinoflagellate pellets, respectively. These were 5 orders of magnitude higher than production rates of free-living bacteria, indicating that copepod fecal pellets are hot spots of pelagic microbial production. The high production was caused primarily by high initial bacterial abundances. Accordingly, production and growth were entirely uncoupled in diatom pellets. There were no increases in abundance of attached bacteria on any of the 3 diets, indicating that the produced bacterial cells were released from the fecal pellets. Attached bacteria had a higher ectoenzymatic activity than free-living bacteria, but their production and ectoenzymatic activity were uncoupled and they only assimilated a minor fraction of the released DOC. DOC was therefore released favoring free-living microbes. The chitinase activity, which increased several-fold, was coupled to the production of attached bacteria; thus, chitin may play an important role in bacterial production on copepod fecal pellets.KEY WORDS: Copepod fecal pellets · Fecal pellet decomposition · Pelagic DOC flux · Pelagic POC flux · Attached bacterial production · Ectoenzymatic activity Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 33: [279][280][281][282][283][284][285][286][287][288] 2003 cycled (Wotton & Malmqvist 2001, Turner 2002 and that most carbon originating from these fecal pellets remains part of the long-lived organic carbon in the epipelagic (Legendre & Michaud 1998). Hence, the role of fecal pellets from small copepods is that of supplying nutrients to the epipelagic planktonic microbial community rather than maintaining the vertical flux of organic matter.Copepod fecal pellets host an extensive flora of attached bacteria (Gowing & Silver 1983, Bianchi et al. 1992, Delille & Razouls 1994, Hansen & Bech 1996. Breakdown of the fecal pellets is in part governed by microbial decomposition driven by the hydrolytic activity of these bacteria. The potential hydrolytic activity is generally high in pelagic aggregates of organic matter (Karner & Herndl 1992, Smith et al. 1992, and if this potential is fully exploited in fecal pellets, then decomposition and hence recycling of organic matter may occur rapidly....

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Analysis ofN-acetylglucosamine metabolism in the marine bacteriumPirellulasp. strain 1 by a proteomic approach

et al. 2002

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Pirellula sp. strain 1 is a marine bacterium that can grow with the chitin monomer N-acetylglucosamine as sole source of carbon and nitrogen under aerobic conditions, and that is a member of the bacterial phylum Planctomycetes. As a basis for the proteomic studies we quantified growth of strain 1 with N-acetylglucosamine and glucose, revealing doubling times of 14 and 10 h, respectively. Studies with dense cell suspensions indicated that the capacity to degrade N-acetylglucosamine and glucose may not be tightly regulated. Proteins from soluble extracts prepared from exponential cultures grown either with N-acetylglucosamine or glucose were separated by two-dimensional gel electrophoresis and visualized by fluorescence staining (Sypro Ruby). Analysis of the protein patterns revealed the presence of several protein spots only detectable in soluble extracts of N-acetylglucosamine grown cells. Determination of amino acid sequences and peptide mass fingerprints from tryptic fragments of the most abundant one of these spots allowed the identification of the coding gene on the genomic sequence of Pirellula sp. strain 1. This gene showed similarities to a dehydrogenase from Bacillus subtilis, and is closely located to a gene similar to glucosamine-6-phosphate isomerase from B. subtilis. Genes of two other proteins expressed during growth on N-acetylglucosamine as well as on glucose were also identified and found to be similar to a glyceraldehyde-3-phosphate-dehydrogenase and a NADH-dehydrogenase, respectively. Thus the coding genes of three proteins expressed during growth of Pirellula sp. strain 1 on carbohydrates were identified and related by sequence similarity to carbohydrate metabolism.

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Hydrolysis and mineralization of chitin in the Delaware Estuary

Cited by 68 publications

References 27 publications

Uncoupling of chitinase activity and uptake of hydrolysis products in freshwater bacterioplankton

Uncoupling of chitinase activity and uptake of hydrolysis products in freshwater bacterioplankton

Fate of organic carbon released from decomposing copepod fecal pellets in relation to bacterial production and ectoenzymatic activity

Analysis ofN-acetylglucosamine metabolism in the marine bacteriumPirellulasp. strain 1 by a proteomic approach

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