In conclusion, purified sakacin A shows a dual mechanism of action: (1) it acts rapidly by changing the electrical charge distribution across the membrane and consequently dissipating the PMF; and (2) it slowly breaks down cell walls of sensitive bacteria, acting on both the polysaccharide and peptide components of the cell wall peptoglycan. This second activity might be useful
to decrease the number of bacteria that compete for limiting nutrients in the same environment (Nielsen et al., 2003). The strong anti-Listeria activity of sakacin A, the high bacteriocin titer obtained at the end of the purification, and the application of a low-cost media formulation pave the use of this bacteriocin GSI-IX in vivo as an antimicrobial agent in food systems to prevent the growth of spoilage and pathogen bacteria and improve quality, safety, and food shelf life. “
“The phylogenetic diversity of archaeal 16S rRNA genes in a thermoacidic spring field of
Ohwakudani, Hakone, Japan, was investigated by PCR-based analysis using a novel Archaea-specific primer designed in the present study. Clone libraries of archaeal 16S rRNA genes were constructed from hot water (78 °C) and mud (28 °C) samples by PCR using a newly designed forward primer and a previously reported forward primer with reverse primers. Most phylotypes found in the libraries from the hot water sample were related to cultured (hyper)thermophiles. The phylotypes and their detection frequencies from the hot water sample Selleck Dapagliflozin were similar for the libraries amplified with the two different primer sets. In contrast, phylotypes having a low similarity (<95%) to cultured Archaea were found in the libraries from the mud sample. Immune system Some of the phylotypes were relatively close to members of Thermoplasmata (80–93% similarity) and the others were not clearly affiliated with Crenarchaeota and Euryarchaeota, but related
to Thaumarchaeota and Korarchaeota. The phylotypes and their detection frequencies were significantly different between the two libraries of the mud sample. Our results from the PCR-based analysis using the redesigned primer suggest that more diverse, uncultured Archaea are present in acidic environments at a low temperature than previously recognized. PCR-based analysis targeting the 16S rRNA gene has revealed that diverse yet-uncultivated prokaryotes are present in natural environments (Pace, 1997; Schleper et al., 2005). It is assumed that cultured species account for <1% of the total prokaryotes living on Earth (Amann et al., 1995). ‘Universal’ oligonucleotide primers for the domain Bacteria or Archaea have been used for gene amplification with PCR (Lane, 1991; Delong, 1992).