A xylanase produced by the rumen anaerobic protozoan<i>Polyplastron multivesiculatum</i>shows close sequence similarity to family 11 xylanases from Gram-positive bacteria

Devillard, Estelle; Newbold, C. J.; Scott, Karen P.; Forano, Evelyne; Wallace, R. J.; Jouany, J. P.; Flint, Harry J.

doi:10.1111/j.1574-6968.1999.tb08837.x

Cited by 53 publications

(8 citation statements)

References 23 publications

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“…This result agrees with previously published observations that genes acquired by HGT in Actinobacteria mostly originated from beta- and gamma-Proteobacteria [6]. The genes acquired by HGT in fungi [61] and HGT in ciliates such as T. thermophila [26], [62] mostly originated from bacteria. D. discoideum may have transferred the pyr-redox gene to Mycobacterium spp.…”

Section: Discussionsupporting

confidence: 92%

The Genealogic Tree of Mycobacteria Reveals a Long-Standing Sympatric Life into Free-Living Protozoa

et al. 2012

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Free-living protozoa allow horizontal gene transfer with and between the microorganisms that they host. They host mycobacteria for which the sources of transferred genes remain unknown. Using BLASTp, we searched within the genomes of 15 mycobacteria for homologous genes with 34 amoeba-resistant bacteria and the free-living protozoa Dictyostelium discoideum. Subsequent phylogenetic analysis of these sequences revealed that eight mycobacterial open-reading frames (ORFs) were probably acquired via horizontal transfer from beta- and gamma-Proteobacteria and from Firmicutes, but the transfer histories could not be reliably established in details. One further ORF encoding a pyridine nucleotide disulfide oxidoreductase (pyr-redox) placed non-tuberculous mycobacteria in a clade with Legionella spp., Francisella spp., Coxiella burnetii, the ciliate Tetrahymena thermophila and D. discoideum with a high reliability. Co-culturing Mycobacterium avium and Legionella pneumophila with the amoeba Acanthamoeba polyphaga demonstrated that these two bacteria could live together in amoebae for five days, indicating the biological relevance of intra-amoebal transfer of the pyr-redox gene. In conclusion, the results of this study support the hypothesis that protists can serve as a source and a place for gene transfer in mycobacteria.

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Section: Discussionsupporting

confidence: 92%

The Genealogic Tree of Mycobacteria Reveals a Long-Standing Sympatric Life into Free-Living Protozoa

et al. 2012

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“…Some marine algae are also reported to secrete xylanases in extracellular environment (Polizeli et al 2005 ). Xylanases of protozoan and crustacean origin are also reported (Devillard et al 1999 ; Polizeli et al 2005 ). Unusual xylanases from the gut of insects have been studied (Roy et al 2003 ; Brennan et al 2004 ).…”

Section: Introductionmentioning

confidence: 90%

Optimization of fermentation media and growth conditions for microbial xylanase production

Kalim

Ali

2016

3 Biotech

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Efficiency of cellulase-free xylanases is one of the determining factors in paper and pulp industries. Use of microbes which can produce cellulase-free xylanases may help to overcome the current challenges in kraft pulp processing. Isolation and screening of microorganisms from local samples offers a possibility for obtaining the potential microbes for this purpose. This research was therefore aimed to collect, screen, characterize and identify potential cellulase-free xylanase producers. A total of 313 microbial isolates were collected while using selective media (EBAM and XAM) to determine the xylanolytic potential of microbes. Qualitative and quantitative analyses were performed and finally 11 bacterial and 6 fungal strains were selected for characterization and identification. The potential isolates were identified as Bacillus pumilus (388.82 U/mg), Bacillus safensis (385.26 U/mg), Aspergillus flavus (493.33 U/mg) and Aspergillus niger (419.33 U/mg). Optimization of the microbial strains while using agro-industrial waste is suggested.

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“…Using these techniques we and others have been able to isolate and characterize genes from a range of rumen protozoa ( McEwan et al, 1999 ; Newbold et al, 2005 ; Belzecki et al, 2007 ; Boxma et al, 2007 ). This includes a wide range of fibrolytic enzymes a number of which have been found to contain multiple domains with binding domains and putative chimeric constructs being observed suggesting a highly evolved fibrolytic capacity in the rumen ciliates ( Devillard et al, 1999 , 2003 ; Takenaka et al, 1999 , 2004 ; Wereszka et al, 2004 ; Bera-Maillet et al, 2005 ). This observation has been confirmed by recent metagenomic screening of protozoal glucosidases and eukaryotic metatranscriptomes that have confirmed that a diverse range of diverse glycoside hydrolases are present in the rumen protozoa ( Findley et al, 2011 ; Qi et al, 2011 ).…”

Section: Functional Genes In Rumen Ciliate Protozoamentioning

confidence: 99%

The Role of Ciliate Protozoa in the Rumen

et al. 2015

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First described in 1843, Rumen protozoa with their striking appearance were assumed to be important for the welfare of their host. However, despite contributing up to 50% of the bio-mass in the rumen, the role of protozoa in rumen microbial ecosystem remains unclear. Phylogenetic analysis of 18S rDNA libraries generated from the rumen of cattle, sheep, and goats has revealed an unexpected diversity of ciliated protozoa although variation in gene copy number between species makes it difficult to obtain absolute quantification. Despite repeated attempts it has proven impossible to maintain rumen protozoa in axenic culture. Thus it has been difficult to establish conclusively a role of ciliate protozoa in rumen fiber degradation. The development of techniques to clone and express ciliate genes in λ phage, together with bioinformatic indices to confirm the ciliate origin of the genes has allowed the isolation and characterization of fibrolytic genes from rumen protozoa. Elimination of the ciliate protozoa increases microbial protein supply by up to 30% and reduces methane production by up to 11%. Our recent findings suggest that holotrich protozoa play a disproportionate role in supporting methanogenesis whilst the small Entodinium are responsible for much of the bacterial protein turnover. As yet no method to control protozoa in the rumen that is safe and practically applicable has been developed, however a range of plant extract capable of controlling if not completely eliminating rumen protozoa have been described.

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A xylanase produced by the rumen anaerobic protozoanPolyplastron multivesiculatumshows close sequence similarity to family 11 xylanases from Gram-positive bacteria

Cited by 53 publications

References 23 publications

The Genealogic Tree of Mycobacteria Reveals a Long-Standing Sympatric Life into Free-Living Protozoa

The Genealogic Tree of Mycobacteria Reveals a Long-Standing Sympatric Life into Free-Living Protozoa

Optimization of fermentation media and growth conditions for microbial xylanase production

The Role of Ciliate Protozoa in the Rumen

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