Presence in rumen bacterial and protozoal populations of enzymes capable of degrading fungal cell walls

Morgavi, Diego; Sakurada, Masaru; Tomita, Yoshifumi; Onodera, Ryoji

doi:10.1099/00221287-140-3-631

Cited by 51 publications

(44 citation statements)

References 34 publications

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“…This may have been caused by different concentrations of protein in the crude enzyme preparation, as well as the condition of the protozoa after incubation with antibiotics. Similar results of enzymatic studies were obtained by Morgavi et al (1994b). However, it should be noted that the cited authors worked on a mixed population of protozoa and used specific substrates to determine exochitinolytic activity.…”

Section: Discussionsupporting

confidence: 69%

Chitin as a source of energy for rumen ciliates

et al. 2015

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Section: Discussionsupporting

confidence: 69%

Chitin as a source of energy for rumen ciliates

et al. 2015

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“…Growth rates were determined by Klett meter readings of liquid cultures incubated at various temperatures. Four distinct extracellular enzyme activities were assayed, between 2° and 37°C, as follows: (1) protein hydrolysis was detected by clearing zones on DMB agar with skim milk added (15 g/L) (Lichenstein et al, 1992); (2) esterase activity was detected by precipitation zones on DMB agar supplemented with 1% Tween-20 (ICN Biomedicals) (Jensen, 1983); (3) chitin hydrolysis was detected by clearing zones on DMB agar containing colloidal chitin (15g/L) (Lingappa and Lockwood, 1961;Morgavi et al, 1994); and (4) starch hydrolysis was indicated by clear zones on iodine-stained DMB agar with starch (15g/L).…”

Section: Jf Biddle Et Al Enrichment and Cultivation Of Microorganimentioning

confidence: 99%

Enrichment and Cultivation of Microorganisms from Sediment from the Slope of the Peru Trench (ODP Site 1230)

Biddle

House

Brenchley

2005

Proceedings of the Ocean Drilling Program, 201 Scientific Results

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The deep biosphere is estimated to hold a significant percentage of the Earth's prokaryotic biomass; however, little is known about the organisms in this environment. Here, we describe investigations of the diversity of microorganisms enriched from surface and subsurface sediment collected during Leg 201 of the Ocean Drilling Program at Site 1230 on the slope of the Peru Trench. This site contains methane hydrates, high levels of organic matter, and high direct cell counts, all of which indicate the potential for thriving microbial populations. To investigate these populations, we examined prokaryotes in samples from seafloor to 258 meters below seafloor (mbsf) using both cultivation and molecular methods. From seafloor samples, we cultivated isolates representing the genera Photobacterium, Shewanella, and Halomonas. The population found in an enrichment cultivated at low temperatures, 0.67 mbsf, contained many cell morphologies and deoxyribonucleic acid (DNA) signatures, but this population, except for a Vibrio sp., was difficult to separate and grow as pure cultures. Most isolates produced extracellular lytic enzymes that were active at low temperatures. Methanogens have been expected to play a large role in the creation of methane hydrates in the sediment; therefore, we also attempted to enrich for psychrophilic methanogens. No methane was found above background levels in anaerobic enrichments incubated for 2 yr, nor was any 16S ribosomal DNA detected following amplification using archaeal primers with DNA extracted from these incubated cultures. These results illus-1 Biddle, J.F., House, C.H., and Brenchley, J.E., 2005. Enrichment and cultivation of microorganisms from sediment from the slope of the Peru Trench (ODP Site 1230).

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“…Coincubations of protozoa with fungi have shown that the protozoa are able to both ingest and digest fungi (47). Morgavi et al (37) found considerable chitinase activity in samples of mixed rumen protozoa, which would account for their predatory activity on the rumen fungi (30,54). No effects were noted when a washed preparation of small protozoa (over 95% Dasytricha ruminantium) was incubated with the rumen fungus Neocallimastix frontalis.…”

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confidence: 99%

Antibiosis between Ruminal Bacteria and Ruminal Fungi

Dehority

Tirabasso

2000

Appl Environ Microbiol

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Cellulose digestion, bacterial numbers, and fungal numbers were monitored over time in vitro by using a purified cellulose medium with and without antibiotics (penicillin and streptomycin). All fermentations were inoculated with a 1:10 dilution of whole rumen contents (WRC). Without antibiotics, cellulose digestion was higher (P < 0.01) at 24, 30, 48, and 72 h; fungi had almost disappeared by 24 h, while bacterial concentrations increased over 100-fold in 24 h and then decreased gradually up to 72 h. In those fermentations with added antibiotics, fungal concentrations increased 4-fold by 30 h and up to 42-fold at 72 h; bacterial concentrations were markedly reduced by 24 h and remained low through 72 h. Similar results were obtained with ground alfalfa as a substrate. In further studies, the in vitro fermentation of purified cellulose without antibiotics was stopped after 18 to 20 h, and the microbial population was killed by autoclaving. Antibiotics were added to half of the tubes, and all tubes were reinoculated with WRC. After 72 h, extensive cellulose digestion had occurred in those tubes without antibiotics, as compared to very low cellulose digestion with added antibiotics. The extent of this inhibition was found to increase in proportion to the length of the initial fermentation period, suggesting the production of a heat-stable inhibitory factor or factors. The inhibitory activity was present in rumen fluid, could be extracted from lyophilized rumen fluid (LRF) with water, and was stable in response to proteolytic enzymes. In addition, the water-extracted residue of LRF was found to contain growth factor activity for rumen fungi in vitro.The flagellated microorganisms observed in rumen contents by Liebetanz in 1910 (36) and Braune in 1913 (13) were originally believed to be flagellate protozoa. However, in a series of classic studies, Orpin (39-45) determined that these organisms were actually flagellated zoospores of anaerobic fungi. Although concentrations of the fungi are relatively low in comparison to those of the bacteria and ciliate protozoa, they possess a wide range of enzymes which are capable of hydrolyzing most of the structural polysaccharides occurring in plant cell walls (21,26,35,48,53,55). The fungi also appear to be superior to the rumen bacteria in their ability to break down and degrade the structural barriers in plant material (2). They are able to weaken and partially or fully degrade the more recalcitrant plant tissues as well as penetrate the cuticle barrier (3, 5, 34). When fungi were removed from the rumen, both feed intake and fiber digestibility were decreased; however, total viable bacteria, cellulolytic bacteria, or ciliate protozoal concentrations were not affected (24). Based on in vitro studies with rumen fluid, using antibiotics and a fungicide to selectively culture either the bacteria or fungi, Akin and coworkers (1, 56) concluded that the bacteria were the most active fiberdigesting organisms, even though fungal numbers were increased in the antibiotic-treated cultur...

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Presence in rumen bacterial and protozoal populations of enzymes capable of degrading fungal cell walls

Cited by 51 publications

References 34 publications

Chitin as a source of energy for rumen ciliates

Chitin as a source of energy for rumen ciliates

Enrichment and Cultivation of Microorganisms from Sediment from the Slope of the Peru Trench (ODP Site 1230)

Antibiosis between Ruminal Bacteria and Ruminal Fungi

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