Repetitive sequence-based PCR (rep-PCR) is a distinctive typing approach that is used to
differentiate between bacterial strains. This method is also useful for studying bacterial diversity
from different sources. In this study, four rep-PCR which are enterobacterial repetitive intergenic
consensus PCR (ERIC-PCR), BOX-PCR, repetitive extragenic palindromic PCR (REP-PCR)
and polytrinucleotide (GTG)5-PCR were evaluated for differentiation of eighteen Escherichia
coli isolates to correct source based on part of intestine and age. These isolates were recovered
earlier from ileal and caecal mucosal contents of chickens at different age. The purpose of this
study was to investigate the efficacy of four rep-PCR methods and composite of rep-PCR
patterns to differentiate E. coli isolates to original sources of part of intestines and age based on
the D index (discriminatory power determined based on Simpson’s index of diversity calculated
at similarity coefficient of 90%). The (GTG)5-PCR had the highest D index (0.9804) for part of
intestine and age factors. The similar D index was observed in the composite of rep-PCR
patterns. The lowest D index was observed in ERIC- and BOX-PCR at 0.9020 and 0.8039 for
part of intestine and age factors, respectively. (GTG)5-PCR was also the most discriminative rep-
PCR observed due to its ability to cluster 14I 3E and 14I 2X isolates, and 14C 1E and 14C 3E
isolates correctly in part of intestine and age factors. It was concluded that (GTG)5-PCR is a
promising tool for discriminating E. coli isolates extracted from chicken intestines.
The effects of phenolic monomers (i.e. rho-coumaric acid, ferulic acid, rho-hydroxybenzaldehyde and vanillin) on the enzymes and fermentation activities of Neocallimastix frontalis B9 grown in ball-milled filter paper and guinea grass media were studied. The enzymes studied were carboxymethylcellulase (CMCase), filterpaperase (FPase), xylanase and beta-glucosidase. At 96 h of incubation, N. frontalis grown in ball-milled filter paper medium produced comparable xylanase and CMCase activities (0.41, 0.5 micromol/min/mg protein) while in guinea grass medium, N. frontalis produced higher xylanase activity than that of CMCase activity (2.35, 0.05 micromol/min/mg protein). The other enzymes activities were low. When N. frontalis was grown in ball-milled filter paper medium, only acetic acid was produced. However, when grown in guinea grass medium, the major end-product was acetate, but propionic, butyric and isovaleric were also produced in lesser amount. Vanillin showed the least inhibitory effects to enzyme activities of N. frontalis B9 grown in both ball-milled filter paper and guinea grass media. For total volatile fatty acid production, all phenolic monomers showed inhibitory effects, but rho-coumaric and ferulic acids were the stronger inhibitors than rho-hydroxybenzaldehyde and vanillin.