• Animal Bioscience
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• 제37권2_spc호
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• pp.396-403
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• 2024

Objective: Monofluoroacetate (MFA) is a potent toxin that blocks ATP production via the Krebs cycle and causes acute toxicity in ruminants consuming MFA-containing plants. The rumen bacterium, Cloacibacillus porcorum strain MFA1 belongs to the phylum Synergistota and can produce fluoride and acetate from MFA as the end-products of dehalorespiration. The aim of this study was to identify the genomic basis for the metabolism of MFA by this bacterium. Methods: A draft genome sequence for C. porcorum strain MFA1 was assembled and quantitative transcriptomic analysis was performed thus highlighting a candidate operon encoding four proteins that are responsible for the carbon-fluorine bond cleavage. Comparative genome analysis of this operon was undertaken with three other species of closely related Synergistota bacteria. Results: Two of the genes in this operon are related to the substrate-binding components of the glycine reductase protein B (GrdB) complex. Glycine shares a similar structure to MFA suggesting a role for these proteins in binding MFA. The remaining two genes in the operon, an antiporter family protein and an oxidoreductase belonging to the radical S-adenosyl methionine superfamily, are hypothesised to transport and activate the GrdB-like protein respectively. Similar operons were identified in a small number of other Synergistota bacteria including type strains of Cloacibacillus porcorum, C. evryensis, and Pyramidobacter piscolens, suggesting lateral transfer of the operon as these genera belong to separate families. We confirmed that all three species can degrade MFA, however, substrate degradation in P. piscolens was notably reduced compared to Cloacibacillus isolates possibly reflecting the loss of the oxidoreductase and antiporter in the P. piscolens operon. Conclusion: Identification of this unusual anaerobic fluoroacetate metabolism extends the known substrates for dehalorespiration and indicates the potential for substrate plasticity in amino acid-reducing enzymes to include xenobiotics.

• Asian-Australasian Journal of Animal Sciences
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• 제30권9호
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• pp.1261-1269
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• 2017

Objective: The effect of flavonoids from alfalfa on the microbial flora was determined using molecular techniques of 16S ribosome deoxyribonucleic acid (rDNA) analysis. Methods: Four primiparous Holstein heifers fitted with ruminal cannulas were used in a $4{\times}4$ Latin square design and fed a total mixed ration to which alfalfa flavonoids extract (AFE) was added at the rates of 0 (A, control), 20 (B), 60 (C), or 100 (D) mg per kg of heifer BW. Results: The number of operational taxonomic units in heifers given higher levels of flavonoid extract (C and D) was higher than for the two other treatments. The Shannon, Ace, and Chao indices for treatment C were significantly higher than for the other treatments (p<0.05). The number of phyla and genera increased linearly with increasing dietary supplementation of AFE (p<0.05). The principal co-ordinates analysis plot showed substantial differences in the microbial flora for the four treatments. The microbial flora in treatment A was similar to that in B, C, and D were similar by the weighted analysis. The richness of Tenericutes at the phylum level tended to increase with increasing AFE (p = 0.10). The proportion of Euryarchaeota at the phylum level increased linearly, whereas the proportion of Fusobacteria decreased linearly with increasing AFE supplementation (p = 0.04). The percentage of Mogibacterium, Pyramidobacter, and Asteroleplasma at the genus level decreased linearly with increasing AFE (p<0.05). The abundance of Spirochaeta, Succinivibrio, and Suttonella at the genus level tended to decrease linearly with increasing AFE (0.05

• Asian-Australasian Journal of Animal Sciences
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• 제32권1호
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• pp.82-91
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• 2019

Objective: This experiment was conducted to compare the structure and composition of ruminal microorganisms in goats with high and low neutral detergent fibre (NDF) digestibility. Methods: Nineteen crossbred goats were used as experimental animals and fed the same total mixed rations during the 30-day pre-treatment and 6-day digestion trialperiods. All faeces were collected during the digestion period for measuring the NDF digestibility. Then, high and the low NDF digestibility individuals were chosen for the high NDF digestibility group (HFD) and low NDF digestibility group (LFD), respectively. Rumen contents were collected for total microbial DNA extraction. The V4 region of the bacterial 16S rRNA gene was amplified using universal primers of bacteria and sequenced using high-throughput sequencer. The sequences were mainly analysed by QIIME 1.8.0. Results: A total of 18,694 operational taxonomic units were obtained, within 81.98% belonged to bacteria, 6.64% belonged to archaea and 11.38% was unassigned microorganisms. Bacteroidetes, Firmicutes, and Proteobacteria were the predominant microbial phyla in both groups. At the genus level, the relative abundance of fifteen microorganisms were significantly higher (p<0.05) and six microorganisms were extremely significantly higher (p<0.01) in LFD than HFD. Overall, 176 core shared genera were identified in the two groups. The relative abundance of 2 phyla, 5 classes, 10 orders, 13 families and 15 genera had a negative correlation with NDF digestibility, but only the relative abundance of Pyramidobacter had a positive correlation with NDF digestibility. Conclusion: There were substantial differences in NDF digestibility among the individual goats, and the NDF digestibility had significant correlation with the relative abundance of some ruminal microorganisms.

• Restorative Dentistry and Endodontics
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• 제36권6호
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• pp.498-505
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• 2011

연구목적: 본 연구는 원발성 치근단 치주염(primary apical periodontitis)을 갖는 치아에서 임상증상 유무에 따른 미생물 군집의 차이를 GS FLX Titanium pyrosequencing을 이용하여 species level까지 분석하였다. 연구 재료 및 방법: 원발성 치근단 치주염을 갖는 6개의 표본에서 pysequencing을 시행하였다. 중합효소 연쇄반응(PCR)에 의해 얻어진 small-subunit ribosomal RNA의 초가변 영역(hypervariable region)의 amplicon을 이용하여 GS FLX Titanium pyrosequencing 을 시행하였다. 결과: 평균적으로 무증상군 및 증상군에서 각각 10,639 및 45,455개의 16S rRNA sequence을 얻었으며 평균길이는 440bases였다. Ribosomal Database Project Classifier을 이용한 분석결과 142종의 genera 및 13종의 phylum 수준에서의 세균종을 검출하였다. 검출된 13개의 phyla 가운데 Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria, Proteobacteria, Spirochetes, and Synergistetes 종이 상대적으로 호발하였으며, genus 수준에서는 Pyramidobacter, Streptococcus, Leptotrichia이 무증상의 근관의 50%를 차지하였으며, Neisseria, Propionibacterium, Tessaracoccus 균종은 증상이 있는 근관의 69%를 차지하였다. Operational taxonomic units (3%)로 나눈 결과 증상이 없는 치아에서 450개, 증상이 있는 치아에서 1,997개의 species가 발견되었다. 증상이 있는 치아에서 통계적으로 유의성 있게 많은 수의 세균이 검출되었다(p < 0.05). 결론: GS FLX Titanium Pyrosequencing 기법을 통해 원발성 감염근관에서 이전에 검출하지 못했던 다양한 근관내 분포세균을 검출할 수 있었다.