A novel dipeptide, beta-aspartylglycine (beta-DG), has been isolated from tissues of the marine gastropod mollusc Aplysia californica. This compound was detected only in Aplysia and not in other molluscs, such as Helix or Mercenaria, or in lobster or frog. Among the Aplysia tissues, the highest levels of beta-DG were in nervous tissue and in the reproductive tract. beta-DG was assayed by HPLC as the o-phthaldialdehyde derivative and found to be present in all individual, identified neurons at a concentration of approximately 40 pmol/microgram protein. The peptide was identified as beta-DG by gas chromatography-mass spectrometry (GCMS) using trimethylsilyl derivatives prepared before and after acid hydrolysis. It was further characterized as the beta-isomer by TLC, including Rf, atypical blue-gray color with ninhydrin, and a violet color with Cu2+-ninhydrin. A fractionation scheme is described whereby acid-soluble tissue constituents can be divided into acidic, neutral, and basic components using mini ion-exchange columns. This partial purification prior to TLC analysis was necessary to remove compounds that interfered with the isolation of beta-DG.
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http://dx.doi.org/10.1111/j.1471-4159.1984.tb05397.x | DOI Listing |
J Vet Med A Physiol Pathol Clin Med
April 2005
Microbiology and Tumor Biology Center, Karolinska Institutet, Stockholm, Sweden.
Intestinal contents of newborn and young germ-free minipigs and germ-free rats were investigated for the following biochemical parameters - conversion of cholesterol to coprostanol, degradation of beta-aspartylglycine, level of tryptic activity, formation of urobilinogen and the profile of short-chain fatty acids. Additionally, germ-free minipigs and germ-free rats were monoassociated with non-pathogenic strains of Escherichia coli and were investigated for the same biochemical parameters. The conversion of cholesterol to coprostanol, degradation of beta-aspartylglycine, tryptic activity and the short-chain fatty acid profile were similar to those found in previous studies in germ-free animals.
View Article and Find Full Text PDFVet Res Commun
October 2003
Laboratory of Medical Microbial Ecology, Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 5, S-17177 Stockholm, Sweden.
The influence of zinc bacitracin (ZB) and of Bacillus licheniformis on host microbial-related functions in young piglets was investigated by applying the concept of microflora-associated characteristics. Six biochemical parameters were determined before and after weaning in faecal samples from piglets in four litters having access to a diet containing ZB, to a diet containing B. licheniformis, to a diet with both additives, or to a diet with no additives, from 3 weeks of age.
View Article and Find Full Text PDFJ Vet Med A Physiol Pathol Clin Med
May 2002
Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
Intestinal microbial functions reflect cross-talk between a host and its flora, and external factors may influence these functions. The aim of this investigation was to follow the development of six biochemical microbial-related functions of piglets, raised outdoors (OPs) or indoors (IPs), from birth to slaughter age. The following parameters (microflora-associated characteristic; MAC) were consecutively measured at five different ages: production of short-chain fatty acids (SCFA), conversion of cholesterol to coprostanol and of bilirubin to urobilinogens, inactivation of trypsin, degradation of beta-aspartylglycine and of mucin.
View Article and Find Full Text PDFEquine Vet J
July 2000
Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
This study investigated the influence of zinc bacitracin on the intestinal flora of horses. The functionally active intestinal flora was examined in 6 horses during treatment with zinc bacitracin. Utilising gas chromatography, spectrophotometry, gel electrophoresis and paper chromatography, samples were analysed on biochemical markers reflecting the action of parts of the intestinal flora.
View Article and Find Full Text PDFEquine Vet J
May 2000
Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
The aim of this study was to investigate 6 microflora-associated characteristics (MACs) in faecal samples from horses and to compare the results with baselines previously established in other mammals. A MAC is defined as any anatomical structure, physiological, biochemical or immunological characteristic in a host, which has been acted on by microorganisms. When the active microbes are absent, as in germ-free animals and healthy newborn organisms, the corresponding characteristic is defined as germ-free animal characteristic (GAC).
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