scholarly journals Isolation and Partial Characterization of Antagonistic Peptides Produced by Paenibacillus sp. Strain B2 Isolated from the Sorghum Mycorrhizosphere

2005 ◽  
Vol 71 (11) ◽  
pp. 6501-6507 ◽  
Author(s):  
S. Selim ◽  
J. Negrel ◽  
C. Govaerts ◽  
S. Gianinazzi ◽  
D. van Tuinen
Keyword(s):  
Mass Spectrometry ◽  
Molecular Mass ◽  
Polymyxin B ◽  
Antagonistic Activity ◽  
Fatty Acyl ◽  
Size Exclusion ◽  
Side Chain ◽  
Acyl Residue ◽  
Reverse Phase ◽  
Paenibacillus Sp

ABSTRACT Paenibacillus sp. strain B2, isolated from the mycorrhizosphere of sorghum colonized by Glomus mosseae, produces an antagonistic factor. This factor has a broad spectrum of activity against gram-positive and gram-negative bacteria and also against fungi. The antagonistic factor was isolated from the bacterial culture medium and purified by cation-exchange, reverse-phase, and size exclusion chromatography. The purified factor could be separated into three active compounds following characterization by amino acid analysis and by combined reverse-phase chromatography and mass spectrometry (liquid chromatography-mass spectrometry and mass spectrometry-mass spectrometry). The first compound had the same retention time as polymyxin B1, whereas the two other compounds were more hydrophobic. The molecular masses of the latter compounds are 1,184.7 and 1,202.7 Da, respectively, and their structure is similar to that of polymyxin B1, with a cyclic heptapeptide moiety attached to a tripeptide side chain and a fatty acyl residue. They both contain threonine, phenylalanine, leucine, and 2,4-diaminobutyric acid residues. The peptide with a molecular mass of 1,184.7 contains a 2,3-didehydrobutyrine residue with a molecular mass of 101 Da replacing a threonine at the A2 position of the polymyxin side chain. This modification could explain the broader range of antagonistic activity of this peptide compared to that of polymyxin B.

Molecular mass determinations in coal-derived liquids by MALDI mass spectrometry and size-exclusion chromatography

Fuel ◽  
1997 ◽  
Vol 76 (13) ◽  
pp. 1225-1233 ◽  
Author(s):  
Maria-Jesus Lázaro ◽  
Alan A. Herod ◽  
Mike Cocksedge ◽  
Mark Domin ◽  
Rafael Kandiyoti
Keyword(s):  
Mass Spectrometry ◽  
Molecular Mass ◽  
Size Exclusion Chromatography ◽  
Maldi Mass Spectrometry ◽  
Size Exclusion ◽  
Exclusion Chromatography

Structural Features of Large Molecular Mass Material in Coal-Derived Liquids: Catalytic Hydrocracking of the Pyridine-Insoluble Fraction of a Coal-Tar Pitch

2000 ◽  
Vol 6 (1) ◽  
pp. 39-48 ◽  
Author(s):  
V. Begon ◽  
C. Islas ◽  
M.J. Lazaro ◽  
I. Suelves ◽  
A.A. Herod ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecular Mass ◽  
Coal Tar ◽  
Structural Features ◽  
Insoluble Fraction ◽  
Size Exclusion ◽  
Gas Chromatography Mass Spectrometry ◽  
Coal Tar Pitch ◽  
Point Distribution ◽  
Polycyclic Aromatic

The pyridine-insoluble fraction of a coal-tar pitch has been catalytically hydrocracked. The starting sample contained no material that could be observed by gas chromatography/mass spectrometry (GC/MS) or by heated-probe mass spectrometry. The aim of the study was to generate structural information on this narrow cut of large-molecular-mass material, which consisted mainly of compounds boiling above 450°C. A much broader boiling-point distribution was found for hydrocracked products; evidence from all analytical techniques used (size-exclusion chromatography, UV-fluorescence spectroscopy and heated-probe mass spectrometry) indicated a significant reduction of the molecular mass range. A wide variety of aromatic groups was identified in hydrocracked products by heated-probe mass spectrometry, ranging from phenanthrene ( m/z 178) to beyond dibenzocoronene ( m/z 400). Ions corresponding to alkyl ( m/z 43, 57, 71 and 85) and alkenyl groups ( m/z 41, 55, 69 and 83) were detected. The results reflect the ability of the hydrocracking process to cleave bonds within large pitch molecules, releasing the structural units which form the molecules. The structure of the original pyridine-insoluble material may thus be seen as a series of aromatic groups linked by short bridges or small groups, but with some longer aliphatic bridges (C12 and C17) as shown by pyrolysis-GC/MS. Clearly, some molecular species were reduced in mass but still lay above the range of detection by heated-probe mass spectrometry and could not be identified. Although the extent to which large polycyclic aromatic entities themselves have been cracked (or otherwise reduced to smaller polycyclic aromatic groups) cannot be quantitatively discerned from the present data, the hydrocracking of isolated fractions of intractable coal-derived material appears to offer a useful method for probing their structural features.

scholarly journals Purification of bacteriocins using size-exclusion chromatography

2016 ◽  
Vol 11 (2) ◽  
pp. 281 ◽  
Author(s):  
Vivek K. Bajpai ◽  
Irfan A. Rather ◽  
Alshammari Fanar Hamad
Keyword(s):  
Mass Spectrometry ◽  
Ammonium Sulfate ◽  
Size Exclusion Chromatography ◽  
Size Exclusion ◽  
Ammonium Sulfate Precipitation ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Cell Free Supernatant ◽  
Video Clips ◽  
Exclusion Chromatography

<p>The bacteriocin purification involves following main steps. a). Extraction of cell-free-supernatant of bacteria. b). Ammonium sulfate precipitation. c). Dialysis. d). Diafiltration using PVP and e). Size-exclusion chromatography. However, depending on the nature of work, the compound could be further analyzed by reverse-phase HPLC, NMR, mass spectrometry and sequencing.</p><p><strong>Video Clips</strong></p><p><a href="https://youtube.com/v/u1BmWfOTS9w">Part 1</a>: 4 min 52 sec</p><p><a href="https://youtube.com/v/aF45JFnwErc">Part 2</a>: 1 min 47 sec</p>

Studies on Chromatographic Fractioning by Cations Exchangers of a Bovine Hemoglobin Hydrolysate

2018 ◽  
Vol 69 (10) ◽  
pp. 2794-2798
Author(s):  
Alina Diana Panainte ◽  
Ionela Daniela Morariu ◽  
Nela Bibire ◽  
Madalina Vieriu ◽  
Gladiola Tantaru ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Retention Time ◽  
Chromatographic Separation ◽  
Bovine Hemoglobin ◽  
Reverse Phase ◽  
Hplc System ◽  
Fast Flow ◽  
Hydrolysis Of ◽  
Phase Column

A peptidic hydrolysate has been obtained through hydrolysis of bovine hemoglobin using pepsin. The fractioning of the hydrolysate was performed on a column packed with CM-Sepharose Fast Flow. The hydrolysate and each fraction was filtered and then injected into a HPLC system equipped with a Vydak C4 reverse phase column (0.46 x 25 cm), suitable for the chromatographic separation of large peptides with 20 to 30 amino acids. The detection was done using mass spectrometry, and the retention time, size and distribution of the peptides were determined.

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