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New Escherichia coli Study Findings Have Been Reported by S.M. Mate and Co-Researchers (Boundary region between coexisting lipid phases as initial...

July 1, 2014



New Escherichia coli Study Findings Have Been Reported by S.M. Mate and Co-Researchers (Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study)

By a News Reporter-Staff News Editor at Life Science Weekly -- A new study on Proteobacteria is now available. According to news reporting from Buenos Aires, Argentina, by NewsRx journalists, research stated, "Alpha-Hemolysin (HlyA) is a protein toxin, a member of the pore-forming Repeat in Toxin (RTX) family, secreted by some pathogenic strands of Escherichia coli. The mechanism of action of this toxin seems to involve three stages that ultimately lead to cell lysis: binding, insertion, and oligomerization of the toxin within the membrane."

The news correspondents obtained a quote from the research, "Since the influence of phase segregation on HlyA binding and insertion in lipid membranes is not clearly understood, we explored at the meso- and nanoscale-both in situ and in real-time the interaction of HlyA with lipid monolayers and bilayers. Our results demonstrate that HlyA could insert into monolayers of dioleoylphosphatidylcholine/sphingomyelin/cholesterol (DOPC/16:0SM/Cho) and DOPC/24:1SM/Cho. The time course for HlyA insertion was similar in both lipidic mixtures. HlyA insertion into DOPC/16:0SM/Cho monolayers, visualized by Brewster-angle microscopy (BAM), suggest an integration of the toxin into both the liquid-ordered and liquid-expanded phases. Atomic-force-microscopy, imaging reported that phase boundaries favor the initial binding of the toxin, whereas after a longer time period the HlyA becomes localized into the liquid-disordered (Ld) phases of supported planar bilayers composed of DOPC/16:0SM/Cho. Our AFM images, however, showed that the HlyA interaction does not appear to match the general strategy described for other invasive proteins."

According to the news reporters, the research concluded: "We discuss these results in terms of the mechanism of action of HlyA."

For more information on this research see: Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study. Biochimica Et Biophysica Acta-Biomembranes, 2014;1838(7):1832-1841. Biochimica Et Biophysica Acta-Biomembranes can be contacted at: Elsevier Science Bv, PO Box 211, 1000 Ae Amsterdam, Netherlands (see also Proteobacteria).

Our news journalists report that additional information may be obtained by contacting S.M. Mate, Univ Natl La Plata, Fac Ciencias Exactas, Dept. of Ciencias Biol, RA-1900 La Plata, Buenos Aires, Argentina. Additional authors for this research include R.F. Vazquez, V.S. Herlax, M.A.D. Millone, M.L. Fanani, B. Maggio, M.E. Vela and L.S. Bakas.

Keywords for this news article include: Argentina, Buenos Aires, South America, Proteobacteria, Escherichia coli, Enterobacteriaceae, Gram-Negative Bacteria

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Source: Life Science Weekly