Factors Affecting the Uptake and Metabolism of Soluble Carbohydrates by the Rumen Ciliate Dasytricha ruminantium Isolated from Ovine Rumen Contents by Filtration

Williams, Alan G.; Harfoot, C. G.

doi:10.1099/00221287-96-1-125

Cited by 49 publications

(53 citation statements)

References 19 publications

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“…Hydrogen and carbon dioxide are metabolic products of anaerobic metabolism of both bacteria (Bryant 1977;Wolin 1979) and protozoa (Abou Akkada and Howard 1960;Prins and Prast 1973;Williams and Harfoot 1976).…”

Section: Introductionmentioning

confidence: 99%

Association of methanogenic bacteria with rumen protozoa

Krumholz¹,

Forsberg²,

Veira³

1983

Can. J. Microbiol.

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Methanogenic bacteria superficially associated with rumen entodiniomorphid protozoa were observed by fluorescence microscopy. A protozoal suspension separated from strained rumen fluid (SRF) by gravity sedimentation exhibited a rate of methane production six times greater (per millilitre) than SRF. The number of protozoa (per millilitre) in the protozoal suspension was three times greater than that of SRF; however, the urease activity of this fraction was half that of SRF. The methanogenic activity of SRF and the discrete fractions obtained by sedimentation of protozoa correlated with the numbers of protozoa per millilitre in each fraction. Gravity-sedimented protozoa, washed four times with cell-free rumen fluid, retained 67-71% of the recoverable methanogenic activity. Thus it is evident from our observations that many methanogens adhere to protozoa and that the protozoa support methanogenic activity of the attached methanogens. When protozoa-free sheep were inoculated with rumen contents containing a complex population of protozoa, methanogenic activity of the microflora in SRF samples was not significantly enhanced.

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Section: Introductionmentioning

confidence: 99%

Association of methanogenic bacteria with rumen protozoa

Krumholz¹,

Forsberg²,

Veira³

1983

Can. J. Microbiol.

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“…The studies reported here were undertaken to (a) confirm the origin and location of the invertase and examine the range of extracellular carbohydrase activity associated with the holotrich protozoa and (b) assess the effect of nutritional and environmental factors on exocellular invertase formation. Certain aspects of this work have been reported previously (33).…”

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confidence: 69%

Exocellular Carbohydrase Formation by Rumen Holotrich Ciliates

Williams

1979

The Journal of Protozoology

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SYNOPSIS Exocellular carbohydrase activity was detected, in the absence of cell lysis, in cell‐free culture supernatant fluids of rumen holotrich ciliates after incubations in buffer systems of varying tonicity, from cell suspensions that were isolated by various technics, and in which bacterial activity had been suppressed by antibiotics. The kinetic characteristics of the holotrich invertases and β–glucosidase from Dasytricha, although having interspecies variations, were the same for the intra‐ and extracellular form of the enzyme. The properties of the invertase activity present in cell‐free rumen contents resembled those of the exocellular enzymes formed by the holotrichs. Invertase activity in the in vitro culture supernatant fluid of Dasytricha ruminantium increased throughout the incubation period and was influenced by the initial pH, temperature, sucrose concentration, and inoculum size. Exocellular holotrich carbohydrase activity was increased when the incubation substrate was not readily utilized by the protozoa. Intracellular carbohydrase activity was also influenced by the carbohydrate substrate.

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“…Further, SBC itself may be an intrinsic factor promoting co-evolution. Rumination is a thermally intensive process: rumen temperatures during active digestion can reach upwards of 46 ° C but typically range between 39 and 42 ° C [Dale et al, 1954;Hungate, 1968;Williams and Harfoot, 1976;MacDonald, 1984;Williams, 1986;Moran, 2005;Beatty et al, 2008aBeatty et al, , 2008bSigner et al, 2010;Turbill et al, 2011]. Semi-reversible damage to neurons and cortical impairment begin at similar temperatures -40 to 41 ° C [Gwozdz et al, 1970[Gwozdz et al, , 1978Millan et al, 1979;Gold et al, 1985]; thus, SBC may be a prerequisite for FF on both physiological and evolutionary scales.…”

Section: Discussionmentioning

confidence: 99%

Augmenting Trait-Dependent Diversification Estimations with Fossil Evidence: A Case Study Using Osmoregulatory Neurovasculature

O’Brien¹

2018

Brain Behav Evol

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When comparative neuromorphological studies are extended into evolutionary contexts, traits of interest are often linked to diversification patterns. Features demonstrably associated with increases in diversification rates and the infiltration or occupation of novel niche spaces are often termed “key innovations.” Within the past decade, phylogenetically informed methods have been developed to test key innovation hypotheses and evaluate the influence these traits have had in shaping modern faunas. This is primarily accomplished by estimating state-dependent speciation and extinction rates. These methods have important caveats and guidelines related to both calculation and interpretation, which are necessary to understand in cases of discrete (qualitative) character analysis, as can be common when studying the evolution of neuromorphology. In such studies, inclusion of additional characters, acknowledgement of character codistribution, and addition of sister clade comparison should be explored to ensure model accuracy. Even so, phylogenies provide a survivor-only examination of character evolution, and paleontological contexts may be necessary to replicate and confirm results. Here, I review these issues in the context of selective brain cooling – a neurovascular-mediated osmoregulatory physiology that dampens hypothalamic responses to heat stress and reduces evaporative water loss in large-bodied mammals. This binary character provides an example of the interplay between sample size, evenness, and character codistribution. Moreover, it allows for an opportunity to compare phylogenetically constrained results with paleontological data, augmenting survivor-only analyses with observable extinction patterns. This trait- dependent diversification example indicates that selective brain cooling is significantly associated with the generation of modern large-mammal faunas. Importantly, paleontological data validate phylogenetic patterns and demonstrate how suites of characters worked in concert to establish the large-mammal communities of today.

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Factors Affecting the Uptake and Metabolism of Soluble Carbohydrates by the Rumen Ciliate Dasytricha ruminantium Isolated from Ovine Rumen Contents by Filtration

Cited by 49 publications

References 19 publications

Association of methanogenic bacteria with rumen protozoa

Association of methanogenic bacteria with rumen protozoa

Exocellular Carbohydrase Formation by Rumen Holotrich Ciliates

Augmenting Trait-Dependent Diversification Estimations with Fossil Evidence: A Case Study Using Osmoregulatory Neurovasculature

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