Interrelationship between Certain Bacteria and the Rumen Ciliate Dasytricha ruminantium

Gutierrez, J.; Hungate, R. E.

doi:10.1126/science.126.3272.511

Cited by 37 publications

(21 citation statements)

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“…In fact the presence of rather more Streptococcus bovis-type,'bacteria in sheep 28 (with entodinja) than in sheep 28 (unfaunated) would appear to be evidence against the previously reported ingestion of S. bovis by Entodinium (Gutierrez & Davis, 1959). However, S. bovis largely disappeared in the rumens containing Polyplastron + Entodinium and the mixed protozoal population.…”

Section: Y K U R I H a R A J M Eadie P N Hobson And S 0 Manncontrasting

confidence: 44%

“…The early experiments of Gutierrez on bacterial ingestion by the holotrich and Entodinium protozoa suggested that ingestion was selective on morphological grounds. (Gutierrez, 1958;Gutierrez & Hungate, 1957;Gutierrez & Davis, 1959). However, later experiments by Coleman (1964) on Entodinium caudatum cultured in vitro suggested that ingestion was non-selective and that the number of bacteria ingested was proportional to their size.…”

Section: Discussionmentioning

confidence: 99%

“…It might therefore compete with starchfermenting bacteria for substrate and this it was hoped might be reflected in viable counts of bacteria on a starch-containing medium. Entodinia have also been said to ingest Gram-positive streptococci (S. bovis) (Gutierrez & Davis, 1959) or to ingest completely non-selectively (in vitro) (Coleman, I 964). It was hoped that the experiments might distinguish between these extremes under in vivo conditions.…”

Section: Discussionmentioning

confidence: 99%

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Relationship between Bacteria and Ciliate Protozoa in the Sheep Rumen

Kurihara¹,

Jm²,

Pn³

et al. 1968

Journal of General Microbiology

105

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S U M M A R YTwo sheep were reared together and then kept on a standard diet over a period of 9 months. The rumen of one sheep contained a mixed population of ciliate protozoal species ; the other was initially unfaunated, then faunated with Entodinium caudatum and then with Entodinium and Polyplastron multivesiculatum. For each sheep diurnal and day-to-day variations in total concentration, and concentration of particular types, of bacteria, in viable counts of bacteria on non-selective and differential media and in concentrations of the different protozoal species, were determined. Measurements were also made of in vitro rates of fermentation, rumen pH and ammonia and volatile fatty-acid concentrations. The presence of protozoa decreased rumen bacterial concentrations and increased ammonia and volatile fatty-acid concentrations. However, these changes were not always completely clear-cut since the protozoa changed the patterns of diurnal variation not only of bacterial numbers but of some metabolic activities and metabolites and also altered the balance of bacterial types. These results are discussed in the context of interactions between bacteria and protozoa and between protozoal species. The main effects of faunation of the rumen seem to be caused by non-selective ingestion of small bacteria by the protozoa.

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Section: Y K U R I H a R A J M Eadie P N Hobson And S 0 Manncontrasting

confidence: 44%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Relationship between Bacteria and Ciliate Protozoa in the Sheep Rumen

Kurihara¹,

Jm²,

Pn³

et al. 1968

Journal of General Microbiology

105

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“…Attachment of bacteria to the cilia and pellicle of D. ruminantium (Imai & Ogimoto, 1978) and also their presence in digestive vacuoles (Gutierrez & Hungate, 1957;Stern et al, 1977) are commonly observed. The possible metabolic interrelationships are uncertain although studies with rumen ciliates and methanogens suggest that these microbial groups interact strongly (Hillman et al, 1988).…”

Section: Discussionmentioning

confidence: 99%

Influence of CO2 and low concentrations of O2 on fermentative metabolism of the rumen ciliate Dasytricha ruminantium

Ellis

McIntyre

Saleh

et al. 1991

Journal of General Microbiology

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The effects of ruminal concentrations of CO, and 0, on glucose-stimulated and endogenous fermentation of the rumen isotrichid ciliate Dusytrichu ruminantium were investigated. Principal metabolic products were lactic, butyric and acetic acids, H, and CO,. Traces of propionic acid were also detected; formic acid present in the incubation supernatants was found to be a fermentation product of the bacteria closely associated with this rumen ciliate. 13C NMR spectroscopy revealed alanine as a minor product of glucose fermentation by D. ruminantiurn. Glucose uptake and metabolite formation rates were influenced by the headspace gas composition during the protozoal incubations. The uptake of exogenously supplied D-ghCOSe was most rapid in the presence of 0, concentrations typical of those detected in sifu (i.e. 1-3 p~) .A typical ruminal gas composition (high CO,, low 0,) led to increased butyrate and acetate formation compared to results obtained using 0,-free N,. At a partial pressure of 66 kPa CO, in N,, increased cytosolic flux to butyrate was observed. At low 0, concentrations (1-3 p~ dissolved in the protozoal suspension) in the absence of CO,, increased acetate and CO, formation were observed and D. ruminantium utilized lactate in the absence of extracellular glucose. The presence of both 0, and CO, in the incubation headspaces resulted in partial inhibition of H2 production by D. ruminantiurn. Results suggest that at the 0, and CO, concentrations that prevail in situ, the contribution made by D. ruminantium to the formation of ruminal volatile fatty acids is greater than previously reported, as earlier measurements were made under anaerobic conditions.

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“…Ciliates in carbon-rich environments, such as the rumen of cattle, use soluble carbohydrates but must also ingest bacteria for growth (Gutiérrez & Hungate 1957). Pelagic choreotrichous ciliates do not appear to directly assimilate fluorescently-labeled macromolecules (Tranvik et al 1993).…”

Section: Introductionmentioning

confidence: 99%

The model high molecular weight DOC compound, dextran, is ingested by the benthic ciliate Uronema marinum but does not supplement ciliate growth

First¹,

Hollibaugh²

2009

Aquat. Microb. Ecol.

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Phagotrophic ciliates are capable of growth solely on dissolved compounds in laboratory cultures. Whether ciliates use dissolved compounds in the environment for growth is unclear. We investigated the ability of the marine benthic ciliate Uronema marinum to ingest a model high molecular weight dissolved organic carbon (HMW-DOC) compound, dextran, at concentrations typical for coastal salt marsh sediments (3 µM to 3 mM C). Ingestion was measured by incubating ciliates with fluorescein-labeled dextran (2000 kDa) and measuring the fluorescence signal of the labeled compound in cells via flow cytometry. Ciliates accumulated dextran (relative to formalin-killed controls) at concentrations as low as 0.1 mg l -1 dextran (3 µM C). Labeled dextran accumulated in food vacuoles and near the buccal cavity; thus, the ingestion of dextran appears to be a consequence of feeding activities rather than transport across the cell membrane via parasomal sac formation. Dextran accumulation did not increase with higher bacterial ingestion rates. Instead, dextran accumulation was greatest at intermediate bacterial concentrations and grazing rates. Ciliate growth rates were measured in treatments amended with model carbon compounds-soluble starch, acetate, and glucose (3 mM C, final concentrations). There was no significant increase in ciliate growth rates with these compounds in either bacteria-free or bacteria-enriched treatments. Rather, growth rates were significantly lower in treatments with DOC addition, indicating that processing of these DOC compounds may incur some energetic cost to these ciliates. KEY WORDS: Ciliate · Microbenthos · Cell metabolism · Benthic food web · Carbohydrates · Pinocytosis Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 57: [79][80][81][82][83][84][85][86][87] 2009 directly assimilate fluorescently-labeled macromolecules (Tranvik et al. 1993). Protists adapted to high concentrations of humic substances appear more likely to ingest HMW-DOC (Legrand & Carlsson 1998). Thus ciliates adapted to high concentrations of HMW-DOC, as found in coastal sediments, may more readily ingest dissolved compounds to supplement energy obtained through bacterivory.In shallow water marine sediments, HMW-DOC is released from the breakdown of plant matter and the production of exopolymeric substances by benthic microalgae (e.g. Wheeler 1976, Smith & Underwood 1998. Bacteria must hydrolyze large macromolecules extracellularly and, in some cases, the absence of specific hydrolytic enzymes can hinder organic matter decomposition (Arnosti 2004). The breakdown of HMW-DOC in ciliate food vacuoles, whether deliberate or fortuitous, would not require additional hydrolytic enzymes (and energy expenditures), allowing ciliates to effectively compete with bacteria for HMW-DOC. Indeed, DOC has been suggested as an energy source for benthic ciliates when the rate of particle ingestion appears lower than required for cell metabolism and growth (Epstein 1997). Ciliates are one of t...

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Interrelationship between Certain Bacteria and the Rumen Ciliate Dasytricha ruminantium

Cited by 37 publications

References 1 publication

Relationship between Bacteria and Ciliate Protozoa in the Sheep Rumen

Relationship between Bacteria and Ciliate Protozoa in the Sheep Rumen

Influence of CO2 and low concentrations of O2 on fermentative metabolism of the rumen ciliate Dasytricha ruminantium

The model high molecular weight DOC compound, dextran, is ingested by the benthic ciliate Uronema marinum but does not supplement ciliate growth

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