PCR cloning and detection of point mutations in the eburicol 14a-demethylase (CYP51) gene from Erysiphe graminis f. sp. hordei, a “recalcitrant” fungus
Molecular studies of some micro-organisms are hampered by the difficulty of obtaining sufficient amounts of nucleic acids. A cloning strategy based on PCR has therefore been used to clone the eburicol 14alpha-demethylase (CYP51) gene of the obligate fungus Erysiphe graminis f. sp. hordei (Egh) using minute amounts of genomic DNA. The CYP51 gene encodes the enzymatic target of a major group of fungicides. Sequencing CYP51 from different Egh isolates revealed the occurrence of two alleles for this gene. An allele-specific PCR assay was developed to detect each CYP51 allele.
Direct-fed microbials commonly have been used to enhance performance or to decrease shedding of foodborne pathogens in beef cattle. Megasphaera elsdenii is a recently introduced probiotic bacteria marketed under the trade name Lactipro (MS-Biotec Inc., Wamego, KS) and is a key lactate-fermenting bacterium in the rumens of cattle fed high-concentrate diets. Megasphaera elsdenii is responsible for metabolizing up to 95% lactic acid within the rumen, and thus is an important species for controlling occurrence of ruminal acidosis. The objective of this study was to evaluate changes in ruminal pH and volatile fatty acid concentration during the transition from a diet with 60% concentrate to a diet containing 80% concentrate after administering five different oral dosages of Lactipro.