Transformation and expression of an anaerobic fungal xylanase in several strains of the rumen bacterium<i>Butyrivibrio fibrisolvens</i>

Gobius, Kari S.; Gong, Xue; Aylward, James; Dalrymple, Brian P.; Swadling, Yolande; McSweeney, Christopher S.; Krause, Denis O.

doi:10.1046/j.1365-2672.2002.01662.x

Cited by 13 publications

(16 citation statements)

References 47 publications

(48 reference statements)

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“…¢brisolvens [195,205]. GH 10 and GH 11 xylanases di¡er in their catalytic properties [206] and it was reasoned that the introduction of a GH 11 xylanase would increase its ability to digest ¢ber [195]. Fiber digestibility could be improved in vitro by more than 28% in comparison with the native untransformed strain [195].…”

Section: Genetically Modi¢ed ¢Ber-degrading Bacteriamentioning

confidence: 99%

Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics

et al. 2003

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The degradation of plant cell walls by ruminants is of major economic importance in the developed as well as developing world. Rumen fermentation is unique in that efficient plant cell wall degradation relies on the cooperation between microorganisms that produce fibrolytic enzymes and the host animal that provides an anaerobic fermentation chamber. Increasing the efficiency with which the rumen microbiota degrades fiber has been the subject of extensive research for at least the last 100 years. Fiber digestion in the rumen is not optimal, as is supported by the fact that fiber recovered from feces is fermentable. This view is confirmed by the knowledge that mechanical and chemical pretreatments improve fiber degradation, as well as more recent research, which has demonstrated increased fiber digestion by rumen microorganisms when plant lignin composition is modified by genetic manipulation. Rumen microbiologists have sought to improve fiber digestion by genetic and ecological manipulation of rumen fermentation. This has been difficult and a number of constraints have limited progress, including: (a) a lack of reliable transformation systems for major fibrolytic rumen bacteria, (b) a poor understanding of ecological factors that govern persistence of fibrolytic bacteria and fungi in the rumen, (c) a poor understanding of which glycolyl hydrolases need to be manipulated, and (d) a lack of knowledge of the functional genomic framework within which fiber degradation operates. In this review the major fibrolytic organisms are briefly discussed. A more extensive discussion of the enzymes involved in fiber degradation is included. We also discuss the use of plant genetic manipulation, application of free-living lignolytic fungi and the use of exogenous enzymes. Lastly, we will discuss how newer technologies such as genomic and metagenomic approaches can be used to improve our knowledge of the functional genomic framework of plant cell wall degradation in the rumen.

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Section: Genetically Modi¢ed ¢Ber-degrading Bacteriamentioning

confidence: 99%

Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics

et al. 2003

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“…1997). Heterologous expression of two fungal ( Neocallimastix patriciarum ) xylanase constructs (xynA and pUMSX in the plasmid vector pUB110) was recently obtained in B. fibrisolvens H17c (Gobius et al. 2001).…”

Section: Introductionmentioning

confidence: 99%

“…The signal peptide in pUMSX encodes a higher proportion of hydrophobic residues to enable more efficient export of the enzyme (Xue et al. 1997; Gobius et al. 2001).…”

Section: Introductionmentioning

confidence: 99%

Expression of a modified Neocallimastix patriciarum xylanase in Butyrivibrio fibrisolvens digests more fibre but cannot effectively compete with highly fibrolytic bacteria in the rumen

et al. 2001

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Aims: This study investigated the competitive abilities of two Neocallimastix patriciarum‐derived xylanases constructs in Butyrivibrio fibrisolvens H17c (xynA and pUMSX) and their ability to compete in vivo. Methods and Results: The digestibility of neutral detergent fibre (NDF) increased during co‐culture of xynA or pUMSX and weakly cellulolytic, but not with highly cellulolytic, ruminococci. Competition studies among xynA, pUMSX and cellulolytic consortia demonstrated that xynA was the fittest. XynA did not persist at high levels in the rumen and was undetectable after 22 days. Conclusions: The construction of recombinant xylanolytic B. fibrisolvens does improve the digestibility of fibre above that of the native, but digestibility is still less than that of the most potent fibre digesters such as ruminococci. Significance and Impact of the Study: Fibre digestion may be improved by genetic manipulation of ruminal bacteria but ecological parameters, such as persistence in vivo and the niche of the organism, must be taken into account.

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“…In this study, four strains of recombinant bacteria were trans-inoculated into sheep before fluoroacetate treatment was conducted and it was observed that the inoculated sheep showed reduced toxicity symptoms compared to uninoculated sheep. As B. fibrisolvens is primarily hemicellulolytic (Dehority 1965;Dehority & Scott 1967), a further recombinant of B. fibrisolvens encoding the genes of plant cell wall-degrading enzymes has been constructed to maximize its fibre degradation, and improve digestibility (Cotta et al 1997;Gobius et al 2002;Krause et al 2001b). However, it still failed to outperfom the far more potent fibrolytic rumen bacteria, Fibrobacter and Ruminococcus species (Krause et al 2003).…”

Section: Trans-inoculation Of Rumen Microbementioning

confidence: 99%

“…Therefore, any introduction of genetically modified strains that can digest crystalline cellulose would go a long way in improving the digestive functions of the rumen, allowing for a more diverse diet. Attempts to introduce genetically modified transformation of B. fibrisolvens with fungal xylanase have been considered unsuccessful due to the inability of these strains to compete with the natural Ruminococcus and Fibrobacter bacteria that are already present in the rumen (Gobius et al 2002). An interesting report of cellulose degradation by Clostridium phytofermentans showed that a single endo-processive GH9 cellulase was a requisite for cellulose degradation (Tolonen et al 2009).…”

Section: The Case Study Of Trans-inoculationmentioning

confidence: 99%

The biochemical and microbiological characteristics of rumen fluid from cattle co-grazed with and without camels as compared to that from the foregut of camels

Suyub¹

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Co-grazing is a common practice under many range conditions. The main advantage of co-grazing is to fully utilize the vegetation sources by taking advantage of the different preferences among animals towards plant species and parts. Hence, this study aimed to establish if co-grazing camels with cattle would lead to changes in the biochemical characteristics in the rumen contents of cattle, and result in different fermentation end products. Rumen contents were collected from two groups of animals at two different locations, the Runnymede Cattle Station at Richmond in northern Queensland, and the Meramist abattoir at Caboolture in Queensland. For the Richmond site, two groups of animals were sampled via stomach tube; cattle co-grazed with camels (n=6) and cattle grazed alone (n=6). For the Caboolture site, foregut contents from three groups of animals were sampled post mortem; camels co-grazed with cattle (n=6), cattle cograzed with camels (n=6), and camels grazed alone (n=6). The ratios of camel to cattle for the Richmond and the Caboolture sites were 1:49 and 1:14 respectively. These ratios were considered adequate for microbial transfer to occur.Foregut fluid samples from all animals were used to inoculate a pre-reduced medium containing Mitchell grass (Astrebla lappacea), Flinders grass (Iseilema spp.), or Lucerne hay (Medicago sativa). Measurements of gas production, volatile fatty acids, and dry matter digestibility were carried out following 48 or 96 h of in vitro incubation at 39 °C.Inocula from cattle co-grazed with camels from Richmond resulted in greater (P< 0.05) dry matter digestibility for Mitchell grass than cattle grazed alone and produced greater (P< 0.05) amounts of n-butyrate. On the other hand, inocula of camels co-grazed with cattle from Caboolture had higher in vitro dry matter digestibility for Mitchell grass and shared the potential for higher dry matter digestibility with cattle co-grazed with camels for lucerne hay. Camels co-grazed with cattle also produced more (P<0.05) n-Butyric acid in the Mitchell grass treatment compared to groups of camels grazed alone and cattle co-grazed with camels. The results from the biochemical analysis suggested that co-grazing may change the ecosystem of the foregut in a number of beneficial ways.A microbiological analysis was carried out to investigate the structure of the bacterial community in each group of animals with high throughput sequencing of 16s rRNA gene using 454 pyrosequencing technology. Using an open source software computational program provided by Quantitative Insights into Microbial Ecology (QIIME), not only was it possible to identify all microbial species within the foregut fluid samples but also it was possible for all data to be analysed and compared systematically.Further analyses to identify the different operational taxonomic units (OTUs) with a similarity threshold of 97% allowed the assessment of observed species (OTUs); species richness (Chao1); and phylogenetic diversity (PD) whole tree metric for each foregut fluid sa...

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Transformation and expression of an anaerobic fungal xylanase in several strains of the rumen bacteriumButyrivibrio fibrisolvens

Cited by 13 publications

References 47 publications

Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics

Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics

Expression of a modified Neocallimastix patriciarum xylanase in Butyrivibrio fibrisolvens digests more fibre but cannot effectively compete with highly fibrolytic bacteria in the rumen

The biochemical and microbiological characteristics of rumen fluid from cattle co-grazed with and without camels as compared to that from the foregut of camels

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