Proteinase Activity in Rumen Ciliate Protozoa

Lockwood, Barbara C.; Coombs, Graham H.; Williams, Alan G.

doi:10.1099/00221287-134-9-2605

Cited by 12 publications

(16 citation statements)

References 22 publications

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“…Moreover, incubations with mannose (Lockwood et al ., 1988) or wide spectrum antibiotics (Heald et al ., 1952) have also been described as effective procedures to lyse holotrich- or protozoal-associated bacteria, respectively. Nonetheless, in preliminary studies, we observed that these compounds could alter the methanogen population and therefore were not used here.…”

Section: Discussionmentioning

confidence: 99%

Study of methanogen communities associated with different rumen protozoal populations

Belanche

Fuente

Newbold

2014

FEMS Microbiology Ecology

117

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Protozoa-associated methanogens (PAM) are considered one of the most active communities in the rumen methanogenesis. This experiment investigated whether methanogens are sequestrated within rumen protozoa, and structural differences between rumen free-living methanogens and PAM. Rumen protozoa were harvested from totally faunated sheep, and six protozoal fractions (plus free-living microorganisms) were generated by sequential filtration. Holotrich-monofaunated sheep were also used to investigate the holotrich-associated methanogens. Protozoal size determined the number of PAM as big protozoa had 1.7–3.3 times more methanogen DNA than smaller protozoa, but also more endosymbiotic bacteria (2.2- to 3.5-fold times). Thus, similar abundance of methanogens with respect to total bacteria were observed across all protozoal fractions and free-living microorganisms, suggesting that methanogens are not accumulated within rumen protozoa in a greater proportion to that observed in the rumen as a whole. All rumen methanogen communities had similar diversity (22.2 ± 3.4 TRFs). Free-living methanogens composed a conserved community (67% similarity within treatment) in the rumen with similar diversity but different structures than PAM (P < 0.05). On the contrary, PAM constituted a more variable community (48% similarity), which differed between holotrich and total protozoa (P < 0.001). Thus, PAM constitutes a community, which requires further investigation as part of methane mitigation strategies.

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Section: Discussionmentioning

confidence: 99%

Study of methanogen communities associated with different rumen protozoal populations

Belanche

Fuente

Newbold

2014

FEMS Microbiology Ecology

117

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“…The connection between protozoa and CH 4 is known, because methanogenic archaea are known to attach to the surface of protozoa, and furthermore appear to live in the cytoplasm of the protozoa as intracellular commensal or symbiotic organisms (Finlay et al 1994). Protozoa are proteolytic (Lockwood et al 1988), which may explain the second connection. However, the relationship between protozoa and acidosis is usually thought to involve the protozoa protecting against acidosis by engulfing starch so that it is not susceptible to bacterial attack (Williams & Coleman, 1992), not the protozoa causing acidosis that seems to be the case in this situation.…”

Section: 'Rumen-up'mentioning

confidence: 99%

Antimicrobial properties of plant secondary metabolites

2004

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Increasing awareness of hazards associated with the use of antibiotic and chemical feed additives has accelerated investigations into plants and their extracts as feed additives. The present review mainly discusses two classes of plant secondary compounds in this context, i.e. essential oils and saponins. The broader potential of plants and their extracts is illustrated by the progress of an EC Framework 5 project, 'Rumen-up'. Dietary inclusion of a commercial blend of essential oils causes markedly decreased NH 3 production from amino acids in rumen fluid taken from sheep and cattle. This effect is mediated partly by the effects on hyper-NH 3 -producing bacteria and the protein-and starch-fermenting rumen bacterium, Ruminobacter amylophilus. Saponin-containing plants and their extracts suppress the bacteriolytic activity of rumen ciliate protozoa and thereby enhance total microbial protein flow from the rumen. The effects of some saponins are transient, because saponins are hydrolysed by bacteria to their corresponding sapogenin aglycones, which are much less toxic to protozoa. Saponins also have selective antibacterial effects that may prove useful in, for example, controlling starch digestion. The 'Rumen-up' project began with a targetted collection of European plants and their extracts, which partners have tested for their effects on rumen proteolysis, protozoa, methanogenesis and lactate production. A success rate of about 5 % in terms of positive hits illustrates that plant secondary compounds, of which essential oils and saponins comprise a small proportion, have great potential as 'natural' manipulators of rumen fermentation to benefit the farmer and the environment in the future.

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“…Lockwood et al 4 ) have shown that the proteolytic activity of Entodiniinae were greater than that of Isotrichids. Furthermore, in these experiments, the proportion of Entodiniinae was more than 98 % of the mixed rumen protozoa.…”

Section: Discussionmentioning

confidence: 99%

High Molecular Weight Protease in Rumen Ciliate Protozoa

Nagasawa

Nagase

Onodera

1994

Bioscience, Biotechnology, and Biochemistry

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Mixed rumen ciliate protozoa (mainly Entodiniinae) from goats have two kinds of protease; one has a pH optimum of 3.0, the other is active at neutral or alkaline pH. The protease active at neutral or alkaline pH was partially purified from the supernatant after centrifugation of sonicated mixed rumen ciliate protozoa. The supernatant was chromatographed on Bio-Gel A-1.5 m and a partially purified protease was obtained. This protease had a molecular weight of more than 400,000. When the sonicated protozoa were heated at 55°C for 15 min, the active peak from the Bio-Gel A-1.5 m column was shifted to a lower molecular weight, 27,000. The high molecular weight protease was strongly activated by high temprature and SDS, and inhibited by E-64 c. The protease degraded many proteins including those found in rumen bacteria. These findings suggest that rumen ciliate protozoa have high molecular weight protease that plays a role in the digestion of feed and bacterial protein.

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Proteinase Activity in Rumen Ciliate Protozoa

Cited by 12 publications

References 22 publications

Study of methanogen communities associated with different rumen protozoal populations

Study of methanogen communities associated with different rumen protozoal populations

Antimicrobial properties of plant secondary metabolites

High Molecular Weight Protease in Rumen Ciliate Protozoa

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