A vaccine against rumen methanogens can alter the composition of archaeal populations.

The objectives of this study were to formulate a vaccine based upon the different species/strains of methanogens present in sheep intended to be immunized and to determine if a targeted vaccine could be used to decrease the methane output of the sheep. Two 16S rRNA gene libraries were used to survey the methanogenic archaea in sheep prior to vaccination, and methanogens representing five phylotypes were found to account for >52% of the different species/strains of methanogens detected. A vaccine based on a mixture of these five methanogens was then formulated, and 32 sheep were vaccinated on days 0, 28, and 103 with either a control or the anti-methanogen vaccine.

Reponses of sheep to a vaccination of entodinial or mixed rumen protozoal antigens to reduce rumen protozoal numbers.

Two rumen protozoa vaccine formulations containing either whole fixed Entodinium or mixed rumen protozoa cells were tested on Merino sheep with the aim of decreasing the number and/or activity of protozoa in the rumen. Negative control (no antigen) and positive control (Tetrahymena corlissi antigens) treatments were also included in the experiment. Blood and saliva were sampled to measure the specific immune response.

16S ribosomal DNA-directed PCR primers for ruminal methanogens and identification of methanogens colonising young lambs.

The population densities and identities of methanogens colonising new-born lambs in a grazing flock were determined from rumen samples collected at regular intervals after birth. Methanogen colonisation was found at the first sampling (1-3 days after birth) and population densities reached around 10(4) methanogens per gram at 1 week of age. Population densities increased in an exponential manner to a maximum of 10(8)-10(9) per gram at 3 weeks of age.

Development and validation of a real-time PCR method to quantify rumen protozoa and examination of variability between entodinium populations in sheep offered a hay-based diet.

PCR and real-time PCR primers for the 18S rRNA gene of rumen protozoa (Entodinium and Dasytricha spp.) were designed, and their specificities were tested against a range of rumen microbes and protozoal groups. External standards were prepared from DNA extracts of a rumen matrix containing known numbers and species of protozoa.

The interaction of phage and biofilms.

Biofilms present complex assemblies of micro-organisms attached to surfaces. they are dynamic structures in which various metabolic activities and interactions between the component cells occur. When phage come in contact with biofilms, further interactions occur dependent on the susceptibility of the biofilm bacteria to phage and to the availability of receptor sites.

Green fluorescent protein as a novel species-specific marker in enteric dual-species biofilms.

Green fluorescent protein (GFP) was used as a tool to examine the interactions between pairs of bacterial species and their effects on subsequent biofilm development over 24 h. A plasmid encoding GFP from Aequorea victoria was transformed into strains of Enterobacter agglomerans and Escherichia coli ATCC 11229. The development of dual-species biofilms, containing one fluorescent and one non-fluorescent partner, was examined using viable counts.