ABSTRACT
This work was conducted to determine if methane emissions from sheep immunized with an anti-methanogen vaccine were significantly lower than methane emissions from non-immunized sheep, to test the effectiveness of two different vaccine formulations (VF) on methane abatement, and to compare methane emissions measured using a closed-circuit respiration chamber and the sulphur-hexafluoride (SF6) tracer technique. Thirty mature wether sheep were randomly allocated to three treatment groups (n = 10). One group received an immunization of adjuvant only on days 0 and 153 (control), a second group received an immunization with a 3-methanogen mix on days 0 and 153 (VF3 + 3), and a third group received an immunization of a 7-methanogen mix on day 0 followed by a 3-methanogen mix on day 153 (VF7 + 3). Four weeks post-secondary immunization, there was a significant 7.7% reduction in methane production per kg dry matter intake in the VF7 + 3 group compared to the controls (P = 0.051). However, methane emissions from sheep immunized with VF7 + 3 were not significantly different when compared to the sheep in the control group (P = 0.883). The average IgG and IgA antibody titres in both plasma and saliva of the VF3 + 3 immunized sheep were four to nine times higher than those immunized with VF7 + 3 (P< 0.001) at both 3 and 6 weeks post-secondary immunization. Data also revealed that SF6 methane estimates were consistently higher than the respiration chamber estimates and that there was no significant correlation between the SF6 methane estimates and the respiration chamber methane estimates (R2 = 0.11).
Subject(s)
Archaea/immunology , Archaea/metabolism , Methane/metabolism , Rumen/microbiology , Sheep/microbiology , Vaccines/immunology , Adjuvants, Immunologic , Animals , Antibodies, Archaeal/analysis , Immunization, Secondary , Immunoglobulin A/analysis , Immunoglobulin G/analysis , Kinetics , Methanobacterium/immunology , Methanobacterium/metabolism , Methanobrevibacter/immunology , Methanobrevibacter/metabolism , Methanomicrobiaceae/immunology , Methanomicrobiaceae/metabolism , Methanosarcina/immunology , Methanosarcina/metabolism , Rumen/immunology , Saliva/immunology , Sheep/immunology , Time Factors , Vaccines/administration & dosageABSTRACT
Methanosarcinae are the only archaeobacteria known to undergo major morphologic changes during growth involving unicellular and multicellular forms, and Methanosarcina mazei S-6 is the only strain for which three distinct forms, packets, single cells, and lamina, have so far been observed. It is reported that two pairs of these forms, either packets and single cells or single cells and lamina, grew and interconverted in medium with the same composition, Ca2+ and Mg2+ concentrations, and growth substrate, and that the two forms in each pair displayed distinctive differences revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting, the same growth medium-substrate notwithstanding.
Subject(s)
Antigens, Bacterial/analysis , Bacterial Proteins/analysis , Methanosarcina/cytology , Antigens, Bacterial/immunology , Antigens, Surface/analysis , Antigens, Surface/immunology , Concanavalin A/metabolism , Immunoblotting , Methanosarcina/chemistry , Methanosarcina/growth & development , Methanosarcina/immunology , MorphogenesisABSTRACT
A novel multicellular form of Methanosarcina mazei S-6 is described. It was termed lamina, and it formed during the exponential growth phase when packets or single cells were grown in 40 mM trimethylamine and a total concentration of 8.3 to 15.6 mM Ca2+ and/or Mg2+, in cultures that were not shaken. A distinct molecular event represented by the increment in expression and a spatial redistribution of an antigen during lamina formation is documented.
