Structure of an acidic polysaccharide from the marine bacterium Pseudoalteromonas aliena type strain KMM 3562T containing two residues of L-serine in the repeating unit

Abstract not available

Structure of an acidic O-specific polysaccharide from marine bacterium Shewanella fidelis KMM 3582T containing Ne-[(S)-carboxyethyl]-Na-(D-galacturonoyl)-L-lysine

The O-specific polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of the marine bacterium Shewanella fidelis type strain KMM 3582T and studied by sugar analysis along with 1H and 13C NMR spectroscopy including one-dimensional NOE in difference mode and two-dimensional experiments. The polysaccharide was found to consist of linear tetrasaccharide repeating units containing Nepsilon-[(S)-1-carboxyethyl]-Nalpha-(D-galacturonoyl)-L-lysine and having the following structure: [See text.] The amide of D-galacturonic acid with Nepsilon-[(S)-1-carboxyethyl]-L-lysine ('alaninolysine', 2S,8S-AlaLys) was found for the first time in nature as a component of the O-specific polysaccharide of Providencia rustigianii O14 (Carbohydr. Res. 2003, 338, 1009-1016)

Measurement of Multi-Stokes Ultrashort Pulse Shapes of Synchronously Pumped Stimulated Raman Scattering on Combined Vibrational Modes in a BaWO₄ Crystal

Multi-Stokes ultrashort pulse shapes and their relative positions of synchronously pumped stimulated Raman scattering (SRS) on combined primary and secondary vibrational modes in a BaWO4 crystal are investigated. An original method of its simultaneous measurement with the help of a streak camera has been developed. The structure of SRS pulses at the pulse shortening effect down to the pulse duration, close to the dephasing time of the secondary Raman mode of the BaWO4 crystal, is registered and analyzed for the detuning of the Raman laser cavity length

The structure of the O−specific polysaccharide of Citrobacter O16 containing glycerol phosphate

The O−specific polysaccharide, obtained by mild acid degradation of Citrobacrer 016 lipopolysaccharide, consists of D−glucose, D−galactose, 2−acetamido−2−deoxy−˜−galactosgel,y cerol and phosphate in the ratios 2 : 2:2 : 1 :l. Selective cleavage of the polysaccharide was carried out by Smith degradation, N−deacetylation−deamination and dephosphorylation with 48 % hydrofluoric acid, which was accompanied by unexpected splitting of one of the glycosidic linkages. The structures of the oligosaccharides thus obtained were established using 'H− and I3C−NMR spectroscopy, including one−dimensional NOE, two−dimensional rotating−frame NOE, homonuclear and heteronuclear 'qC,lH correlation spectroscopy, and, for the Smith degradation product, positive− and negative−ion−mode fast−atom−bombardment MS and MSMS with collision−induced dissociation. On the basis of these data and the results of methylation analysis, it was concluded that the O−specific polysaccharide has the following repeating unit structur

Structure of acidic polysaccharide from the marine bacterium Pseudoalteromonas flavipulchra NCIMB 2033(T)

Abstract not available

Effect of pulsed laser parameters on photoacoustic flow cytometry efficiency in vitro and in vivo

Photoacoustic flow cytometry is one of the most effective approaches to detect "alien" objects in the bloodstream, including circulating tumor cells, blood clots, parasites, and emboli. However, the possibility of detecting high-amplitude signals from these objects against the background of blood depends on the parameters of the laser pulse. So, the dependencies of photoacoustic signals amplitude and number on laser pulse energy (5–150 μJ), pulse length (1, 2, 5 ns), and pulse repetition rate (2, 5, 10 kHz) for the melanoma cells were investigated. First, the PA responses of a melanoma cell suspension in vitro was measured to directly assess the efficiency of converting laser light into an acoustic signal. After it the same dependence with the developed murine model based on constant rate melanoma cell injection into the animal blood flow was tested. Both in vivo and in vitro experiments show that signal generation efficiency increases with laser pulse energy above 15 μJ. Shorter pulses, especially 1 ns, provide more efficient signal generation as well as higher pulse rates. A higher pulse rate also provides more efficient signal generation, but also leads to overheating of the skin. The results show the limits where the photoacoustic flow cytometry system can be effectively used for detection of circulating tumor cells in undiluted blood both for in vitro experiment s and for in vivo murine models