Analysis of fatty acids of the genus Rochalimaea by electron capture gas chromatography: detection of nonanoic acid

Abstract

The fatty acid compositions of Rochalimaea quintana, strains Fuller and Guadalupe, and R. vinsonii, the Canadian vole agent, were determined in an effort to further characterize these bacteria. The cells were saponified with 5% NaOH in 50% methanol and acidified to pH 2. The methanolysates were extracted with chloroform, derivatized with 2,2,2-trichloroethanol, and analyzed using a Hewlett-Packard gas chromatograph equipped with a frequency pulse-modulated electron capture detector and a 3% OV-101 packed-glass column. The fatty acid profiles of the three Rochalimaea strains were similar, with octadecenoic acid (C18:1) the most abundant, followed by octadecanoic (C18:0) and hexadecanoic (C160) acids. Moderate to trace amounts of other acids were also present. Unexpectedly, well-defined peaks of nonanoic acid (C9) were found consistently. A portion of this acid, but not all, was extractable with chloroform. Since Cg is not reported as a usual component of bacteria and most analyses do not include a search for this fatty acid, this study was extended to three strains of Legionella and one of Campylobacter. Comparable results were

Applications of cellular fatty acid analysis.

“…CFAs of Rochalimaea quintana grown on blood agar medium resemble the other rickettsial CFAs except that they lack the 3-OH-C14:0 found in the others. Additional studies have examined Rochalimaea quintana and revealed similar findings (135,162). That C18l: accounts for such a large percentage of the total CFAs (40 to 60%) is a distinctive feature of Rochalimaea quintana.…”

“…That C18l: accounts for such a large percentage of the total CFAs (40 to 60%) is a distinctive feature of Rochalimaea quintana. In contrast to other researchers, Westfall et al (162) analyzed Rochalimaea quintana and related species by electron capture GLC and reported that it contained C9:0. However, they noted that complex media may have been the source of this unusual CFA.…”

Establish the methods to verify the residue of nonanoic acid and sodium chlorate in red beans

“…Red beans are cultivated and harvested mechanically. To facilitate mechanical harvesting, the stems and leaves of red bean plants should be fully dried [18,22]. The use of natural methods may cause inconsistent drying between different parts of the whole plant due to climatic factors like rainfall, and even red bean yield reduction resulted from moldy beans.…”

“…In the detection of nonanoic acid, due to the high polarity and low volatility of fatty acids with a high carbon number, precolumn derivatization combined with gas chromatography-electron capture detection (GC-ECD) has been employed for nonanoic acid detection [6,7,22] to improve the analytical sensitivity. Qualitative and quantitative analysis of fatty acids can also be performed by means of GC without derivatization [10,13,14,17,21], especially for the analysis of lowunsaturation and short-chain fatty acids.…”