Uterine Microbiota Progression from Calving until Establishment of Metritis in Dairy Cows

The objective of this study was to evaluate the progression of the uterine microbiota from calving until establishment of metritis. Uterine swabs (n = 72) collected at 0, 2, and 6 ± 2 days postpartum (dpp) from 12 metritic and 12 healthy cows were used for metagenomic sequencing of the 16S rRNA gene on the Illumina MiSeq platform. A heat map showed that uterine microbiota was established at calving. The microbiota changed rapidly from 0 to 6 ± 2 dpp, with a decrease in the abundance of Proteobacteria and an increase in the abundance of Bacteroidetes and Fusobacteria, which were dominant in metritic cows. Uterine microbiota composition was shared; however, metritic and healthy cows could be discriminated using relative abundance of bacterial genera at 0, 2, and 6 ± 2 dpp. Bacteroides was the main genus associated with metritis because it was the only genus that showed significantly greater abundance in cows with metritis. As the abundance of Bacteroides organisms increased, the uterine discharge score, a measure of uterine health, worsened. Fusobacterium was also an important genus associated with metritis because Fusobacterium abundance increased as Bacteroides abundance increased and the uterine discharge score worsened as the abundance increased. The correlation with uterine discharge score and the correlation with Bacteroides or Fusobacterium showed that other bacteria, such as Helcoccocus, Filifactor, and Porphyromonas, were also associated with metritis. There were also bacteria associated with uterine health, such as “Candidatus Blochmannia,” Escherichia, Sneathia, and Pedobacter.     

Extraction and characterisation of hemicelluloses from maize stem

Introduction – Extraction and characterisation of hemicelluloses are very important for converting them into functional materials and chemicals. Objective – To develop a method for isolation of hemicelluloses from all cell walls. Methodology – Sequential steps using 90% dioxane, 80% acidic dioxane, 100% dimethyl sulphoxide and 8% NaOH were used for extraction of the hemicellulosic preparations (H₁, H₂, H₃ and H₄) from maize stem. Advanced NMR techniques were used for the analysis of native hemicelluloses. Results – Hemicelluloses with high yieldd were isolated from all cell walls, and contained arabinoxylan as the major polysaccharide. H₃ was substituted by α‐l ‐arabinofuranose, α‐d ‐xylopyranose, and acetyl groups (degree of saturation = 0.12/0.09) at O‐3/O‐2 of xylan. H₄ had a long continuous side chain of arabinose residues, and associated closely with non‐cellulosic glucose. The hemicelluloses formed more linkages with guaiacyl lignins, and some p‐coumaric acids built a bridge between hemicelluloses and lignin in maize stem. Conclusion – This modified method is successful for the isolation of hemicelluloses with high yields from all cell walls of maize stem. Copyright © 2010 John Wiley & Sons, Ltd.