The effects of cinnamaldehyde vs. sodium monensin on growth, cell size and cell protein production in Prevotella bryantii B14 and P. ruminicola 23 were studied. B14 strain was visibly more resistant to the action of both compounds. IC50 concentrations of sodium monensin influenced the increase in cell size of both bacterial strains during growth, but more pronounced in strain B14. A similar effect was observed when cinnamaldehyde was used, indicating a possible interference with cell division. The action of cinnamaldehyde was highly concentration dependant in strain B14, but not in 23.
We described the nucA gene, whose product belongs to exonuclease/endonuclease/phosphatase Pfam family, and is involved in the removal of misincorporated uracil from DNA and its reuse. nucA codes for a signal peptide and, based on our results, confers non-specific DNase activity but no AP endonuclease activity, which is required for DNA repair subsequent to base excision. On the other hand, nucA homologues in related organisms from the phylum Bacteroidetes also code for signal peptides. It appears therefore that this feature is conserved and is not a peculiarity limited to P. bryantii.
The membrane fatty acid composition of Escherichia coli becomes conditioned during periodic temperature cycling between 37 and 8 °C. After several cycles of temperature change, the bacteria become locked into a low-temperature physiology. Even after a prolonged incubation at high temperature the membrane fatty acid composition of conditioned cells was similar to that of cold-stressed cells. The study contributes to understanding of the function of membrane systems, which are also the most common targets of different plant extracts and ionophoric antibiotics.
Probiotics are live microorganisms that if consumed at the appropriate number affect the health of the host. Their effects are usually associated with a favorable balance in the gut. In domestic animals they may be associated with improved production efficiency, feed conversion, increased growth rate, etc.. Probiotic feed additives contain in particular G-positive bacteria and some yeasts While the majority of these microbes are in principle safe, some may characteristics that may be harmful to both animals and human.
When disturbed balance of the gut microbiota affects the host physiology probiotic support is very welcomed. The effectiveness of probiotics is a reflection of their activity across different mechanisms which are interconnected in order to perform many useful tasks. They reduce the incidence of infections, regulate the physiology of the host organism mainly through metabolic processes, and strengthen the immune system. Commercially available probiotic products are designed for self-medication and are fully accessible to users. They must be safe and have a low risk of side effects.