Dinkel und Z:oliakie

Spelt wheat (Triticum spelta L.) has not been investigated for the toxicity on coeliac disease patients until now. Because clinical studies are out of considerations for ethical reasons, spelt wheat and coeliac-active bread wheat (Triticum aestivum L.) were compared by the analysis of N-terminal sequences of α-gliadins, which have been proposed to be responsible for the toxic effect. The gliadin fractions of the spelt wheats ‘Roquin’ and ‘Schwabenkorn’ and of the bread wheat ‘Rektor’ were preparatively separated by RP-HPLC and major α-gliadin components were then compared by N-terminal sequence analysis. The results did not reveal any significant difference between spelt and bread wheats within the first 25 positions. For the determination of sequences further from the N-terminus, the gliadin fractions of the spelt wheats were hydrolyzed with pepsin and trypsin. The resulting peptides were successively separated by gel permeation chromatography and RP-HPLC. Those peptides derived from the N-terminal part of α-gliadins were identified by reference peptides isolated previously from bread wheat [this journal 194: 229 (1992)]. Retention times upon RP-HPLC and amino acid compositions of corresponding peptides confirmed the identity of spelt and bread wheat concerning the N-terminal sequences of α-gliadins from position 3 to 56. For these reasons, it can be concluded that spelt wheat is a coeliac-toxic cereal and has to be avoided by coeliac patients.     

Phytate-calcium interactions with soy protein

Solubilities of mixtures of soy protein isolate, calcium and phytate were determined as a function of pH and molar ratio of the components. Below the isoelectric point, phytate and protein solubility profiles paralleled each other, indicating some type of protein-phytate interaction. Addition of phytate shifted the isoelectric point and the minimum solubility to lower values. Between the isoelectric point and pH 6.5, the complex apparently dissociates; addition of phytate results in an increase in the maximum solubility of the phosphorus and the protein, as well as a shift in their solubility profiles. Calcium has no apparent effect on protein solubility in this pH region. Higher pH (>6.5) results in the formation of ternary protein-calcium-phytate complexes and a significant drop in calcium and phosphorus solubility, probably due to formation of insoluble calcium phytate salts.     

Dinkel und Z:oliakie

Zusammenfassung Über Dinkel (Triticum spelta L.) liegen bezüglich sciner Wirkung auf Zöliakiekranke keine Untersuchungen vor. Da eine klinische Testung aus ethischen Gründen nicht in Betracht kommt, wurden Dinkel und Weichweizen (Triticum aestivum L.) in den für die Zöliakieauslösung relevanten N-terminalen Sequenzen der -Gliadine verglichen. Dazu wurden die Gliadinfraktionen der Dinkelsorten Roquin und Schwabenkorn sowie der Weichweizensorte Rektor durch RP-HPLC präparativ getrennt und dominierende -Gliadine N-terminal sequenziert. Innerhalb der ersten 25 Positionen war kein signifikanter Unterschied zwischen den Dinkel- und Weichweizensorten zu erkennen. Zur Erfassung der vom N-Terminus weiter entfernt liegenden Sequenzabschnitte wurden die Gliadinfraktionen der Dinkelsorten mit Pepsin und Trypsin hydrolysiert. Die Partialhydrolysate wurden nacheinander durch Gelpermeationschromatographie und RP-HPLC aufgetrennt. Die aus dem N-terminalen Bereich von -Gliadinen stammenden Peptide wurden mit Hilfe von Referenzpeptiden identifiziert, die in einer früheren Arbeit [diese Zeitschrift 194 229 (1992)] aus einem Gliadinhydrolysat von Weichweizen isoliert wurden. Übereinstimmende Retentionszeiten bei der HPLC und Aminosäurezusammensetzungen der entsprechenden Peptide weisen darauf hin, daß auch in einem längeren N-terminalen Abschnitt (Positionen 3–56) der -Gliadine von Dinkel und Weichweizen identische Sequenzen vorliegen. Es muß daher davon ausgegangen werden, daß auch Dinkel Zöliakie auslöst und von Zöliakiekranken gemieden werden muß.

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Spelt wheat and coeliac disease

Spelt wheat (Triticum spelta L.) has not been investigated for the toxicity on coeliac disease patients until now. Because clinical studies are out of considerations for ethical reasons, spelt wheat and coeliac-active bread wheat (Triticum aestivum L.) were compared by the analysis of N-terminal sequences of -gliadins, which have been proposed to be responsible for the toxic effect. The gliadin fractions of the spelt wheats Roquin and Schwabenkorn and of the bread wheat Rektor were preparatively separated by RP-HPLC and major -gliadin components were then compared by N-terminal sequence analysis. The results did not reveal any significant difference between spelt and bread wheats within the first 25 positions. For the determination of sequences further from the N-terminus, the gliadin fractions of the spelt wheats were hydrolyzed with pepsin and trypsin. The resulting peptides were successively separated by gel permeation chromatography and RP-HPLC. Those peptides derived from the N-terminal part of -gliadins were identified by reference peptides isolated previously from bread wheat [this journal 194: 229 (1992)]. Retention times upon RP-HPLC and amino acid compositions of corresponding peptides confirmed the identity of spelt and bread wheat concerning the N-terminal sequences of -gliadins from position 3 to 56. For these reasons, it can be concluded that spelt wheat is a coeliac-toxic cereal and has to be avoided by coeliac patients.

     

Effect of cisplatin and c-myb antisense phosphorothioate oligodeoxynucleotides combination on a human colon carcinoma cell line in vitro and in vivo

We investigated the effect of c-myb antisense phosphorothioate oligodeoxynucleotides [(S)ODNs] and cisplatin (CDDP) combination on the human colon carcinoma cell line LoVo Dx both in vitro and in nude mice bearing LoVo Dx solid tumour. We show that antisense (S)ODN treatment decreases c-myb mRNA and protein expression, induces growth arrest in the G1 phase of the cell cycle, and inhibits cell proliferation. In vivo treatment with c-myb antisense (S)ODNs results in a reduction in tumour growth. A greater inhibition of cell proliferation in vitro and a higher increase of tumour growth inhibition and growth delay in vivo were obtained with the combination of (S)ODNs and CDDP than when the two agents were administered separately. This comparative study, using the same tumour cell line in vitro and in vivo, suggests that c-myb antisense (S)ODNs might be useful in the therapy of colon cancer in combination with antineoplastic drugs.     

Comparative in vitro and in vivo study of a nitroxyl derivative of 5-fluorouracil (magnizil) on human gastrointestinal tumors

AIMS AND BACKGROUND: There is much interest in nitroxyl derivatives of cytotoxic agents. We evaluated the potential activity of magnizil, a derivative of 5-fluorouracil, on human gastrointestinal tumors in 3 different in vitro and in vivo experimental models. METHODS: The activities of magnizil and 5-fluorouracil were comparatively determined in vitro on the HT29 cell line by a clonogenic assay and on tumor clinical specimens by an antimetabolic assay. The activity of both the drugs against human tumors was also assessed in mice with the subrenal capsule assay. RESULTS: A similar cytotoxic activity was found for magnizil and 5-fluorouracil on the HT29 cell line. As regards human tumors, a lower activity was observed for the nitroxyl derivative than for 5-fluorouracil, with response rates of 25% and 50%, respectively, at comparable concentrations. Moreover, among the tumors transplanted in the subrenal capsule of mice, two were sensitive to magnizil and 3 to 5-fluorouracil. CONCLUSIONS: Even though experimental results on human tumors indicate a somewhat lower activity for magnizil than the parent compound, its low toxicity and the possibility to clinically use high doses suggest the opportunity to further investigate the potential of this new anticancer agent on larger series of colorectal cancers in experimental systems.     

Chlorinated-solvent-free gas chromatographic analysis of biomass containing polyhydroxyalkanoates

An extraction and derivatization method was developed for more environmentally friendly routine quantification of polyhydroxyalkanoates (PHAs) in activated sludge biomass by gas chromatography (GC). This method can be further applied to assess relative changes in biomass carbohydrate levels relating to, for example, glycogen or extracellular polysaccharides. Further, co-extracted principal membrane fatty acids are indicative of relative changes in active biomass. The protocol is attractive for routine assessment because it does not require any chlorinated solvents, which are still almost exclusively used today for PHA analysis by GC. Acidic alcoholysis of dried microbial biomass using 3:1 butanol to concentrated (37%) hydrochloric acid at 100 degrees C for 8 h will hydrolyse and derivatize microbial storage products and membrane lipids. Esters of the hydroxyalkanoates, carbohydrates converted to levulinic acid, and long chain microbial fatty acids are reliably extracted into hexane for gas chromatographic analysis and quantification. Calibration can be achieved with benzoic, 2-hydroxyvaleric, or 2-hydroxycaproic acids as the method reference standards.