Utilizing luminometry for monitoring growth of Listeria monocytogenes in its liquid or gelified monocultures and cocultures with "acid-only" Lactococcus lactis

The light output of a bioluminescent recombinant strain of Listeria monocytogenes increased parallel with its viable cell counts during the exponential phase of the growth both in aerobic monocultures and mixed cultures, but dropped significantly at the commencement of the stationary phase. Suppression of L. monocytogenes by a nisin-less strain of Lactococcus lactis occurred only as an early induction of the stationary state of the target organism. In low-salt cocultures, an inverse linear correlation was found between the logarithmic initial counts of lactic acid bacteria and the extent of growth of Listeria. Decrease of luminometric activity of the bioluminescent test organism indicate sensitively the transformation of the cells into metabolically less active stationary state as a stress-adaptive response to nutrient depletion, "metabolic crowding", or, inimical processes.     

Amplitude,phase, and hybrid ternary modulation modes of a twisted-nematic liquid-crystal display at approximately 400 nm

Applicability of a commercial twisted-nematic liquid-crystal display is examined at approximately 400 nm. Different modulation modes predicted by Jones-matrix calculus are experimentally tested. High contrast amplitude modulation with negligible loss, high contrast and low loss hybrid ternary modulation, and 1.5pi continuous phase delay without intensity modulation and with low loss are presented. Simulation results of a 4f holographic system prove the usefulness of the high contrast for amplitude modulation, and the importance of pi phase difference between high transmission white levels in a hybrid ternary modulation.     

Extrahierung von Farbstoffen aus Lebensmitteln mit quatern?ren Ammoniumverbindungen

Zusammenfassung Cetyl-trimethyl-ammoniumbromid bildet mit den in Ungarn zur Färbung von Lebensmitteln und Getränken benutzten Farbstoffen Verbindungen, die in Wasser nicht, oder nur in geringem Ausmaß, in organischen Lösungsmitteln jedoch gut löslich sind, was die quantitative Extrahierung der Farbstoffe aus Lebensmitteln und Getränken ermöglicht.Bei Untersuchung der Infrarotspektren konnte festgestellt werden, daß die sich entwickelnden Verbindungen Komplexe sind und die Koordination zwischen den Azo- bzw. Carbonylgruppen der Farbstoffmolekeln und dem quaternären Stickstoff zustande kommt. Die Komplexe können mit Kupferron, dem Ammoniumsalz des Phenyl-nitroso-hydroxylamins, gespalten werden, so daß die Farbstoffe nach Komplexbildung und Extrahierung in ihren originalen Zustand zurückversetzt werden können.Ein Vorteil dieser Methode ist, daß die Extrahierung der Farbstoffe bei Zimmertemperatur ohne saure oder alkalische Behandlung durchgeführt werden kann. Mit dieser Methode können die in Erfrischungsgetränken, gefälschtem Wein, Konfitüren, Lebkuchen und Kompott enthaltenen Farbstoffe quantitativ extrahiert und bestimmt werden.     

Results of an Extensive Search for "S&T Indicators" on the Web: A Content Analysis

In this study we carried out a content analysis of Web pages containing the search term "S&T indicators", which were located by an extensive search of the Web. Our results clearly show that the Web is a valuable information source on this topic. Major national and international institutions and organizations publish the full text of their reports on the Web, or allow free downloading of these reports in non-html formats. In addition to direct information, a number of pages listing and linking to major reports, programs and organizations were also located.     

A new look at radicals in cigarette smoke

Radicals in cigarette smoke have been proposed to contribute to the harm caused by cigarette smoking. For the first time, using HPLC and high-resolution mass spectrometry analysis of stable radical adducts, we have identified specific radical species in cigarette smoke: 7 acyl and 11 alkylaminocarbonyl radicals. Their combined abundance measured in fresh whole smoke from a single 2R4F cigarette is approximately 225 nmol (1.4 x 10(17) radicals). The fiberglass Cambridge filter pad conventionally employed to separate the gas phase from mainstream smoke was found to reduce the apparent yield of these radicals, introducing artifacts of measurement. The long-accepted steady-state mechanism for the formation of carbon-centered radicals in cigarette smoke involving NO2 chemistry cannot account for these newly identified radicals, and it does not in general appear to be a major source of carbon-centered radicals in fresh mainstream cigarette smoke. Consequently, we suggest that the precise nature of radicals in cigarette smoke warrants reexamination.     

Anti yeast activities of some essential oils in growth medium, fruit juices and milk

The anti-yeast activities of four essential oils (EOs) from clary sage, juniper, lemon and marjoram against wild-type isolates of the food-related yeasts Geotrichum candidum, Pichia anomala, Saccharomyces cerevisiae and Schizosaccharomyces pombe in malt extract (ME) medium, apple juice and milk were investigated. Minimal inhibitory concentrations (MICs) for the EOs and their main components were determined and the checkerboard method was used to calculate fractional inhibitory concentration (FIC) indices for the combinations of EOs or components. The most sensitive yeast was S. pombe (MICs of 0.0625-0.125 μl/ml) while G. candidum proved to be the most insensitive (MICs of 0.5-2 μl/ml). In general, the lag phases were lengthened by increasing EO concentrations, while significant reduction of growth rates was obtained only at the highest EO concentrations. The anti-yeast effects of the EOs were good in the acidic pH range optimal for yeasts growth. Combinations of juniper and clary sage EOs resulted in additive effects in the case of S. cerevisiae and G. candidum, but all other combinations showed no interaction. The combination of α-pinene and limonene led to synergism, while the combination of α-pinene with linalool resulted in an additive effect. Cloudy apple juice protected the yeasts against the effect of lemon EO: the lag phases were shorter and the growth rates higher than in clear apple juice. Lemon EO decreased the growth rate of G. candidum in skimmed milk in a dose-independent manner. Our results show that by adding lemon EO to clear apple juice a new, harmonic taste can be achieved and open storage time could be prolonged.     

Proteomic analysis of cerebrospinal fluid in a fulminant case of multiple sclerosis

Multiple Sclerosis (MS) is a chronic disease, but in rare fulminant cases rapid progression may lead to death shortly after diagnosis. Currently there is no diagnostic test to predict disease course. The aim of this study was to identify potential biomarkers/proteins related to rapid progression. We present the case history of a 15-year-old male MS patient. Cerebrospinal fluid (CSF) was taken at diagnosis and at the time of rapid progression leading to the patient's death. Using isobaric tag labeling and nanoflow liquid chromatography in conjunction with matrix assisted laser desorption/ionization time of flight tandem mass spectrometry we quantitatively analyzed the protein content of two CSF samples from the patient with fulminant MS as well as one relapsing-remitting (RR) MS patient and one control headache patient, whose CSF analysis was normal. Seventy-eight proteins were identified and seven proteins were found to be more abundant in both fulminant MS samples but not in the RR MS sample compared to the control. These proteins are involved in the immune response, blood coagulation, cell proliferation and cell adhesion. In conclusion, in this pilot study we were able to show differences in the CSF proteome of a rapidly progressing MS patient compared to a more typical clinical form of MS and a control subject.     

Quantifying nonthermal inactivation of Listeria monocytogenes in European fermented sausages using bacteriocinogenic lactic acid bacteria or their bacteriocins: a case study for risk assessment

Listeria monocytogenes NCTC10527 was examined with respect to its nonthermal inactivation kinetics in fermented sausages from four European countries: Serbia-Montenegro, Hungary, Croatia, and Bosnia-Herzegovina. The goal was to quantify the effect of fermentation and ripening conditions on L. monocytogenes with the simultaneous presence or absence of bacteriocin-producing lactic acid bacteria (i.e., Lactobacillus sakei). Different models were used to fit the experimental data and to calculate the kinetic parameters. The best model was chosen based on statistical comparisons. The Baranyi model was selected because it fitted the data better in most (73%) of the cases. The results from the challenge experiments and the subsequent statistical analysis indicated that relative to the control condition the addition of L. sakei strains reduced the time required for a 4-log reduction of L. monocytogenes (t(4D)). In contrast, the addition of the bacteriocins mesenterocin Y and sakacin P decreased the t(4D) values for only the Serbian product. A case study for risk assessment also was conducted. The data of initial population and t(4D) collected from all countries were described by a single distribution function. Storage temperature, packaging method, pH, and water activity of the final products were used to calculate the inactivation of L. monocytogenes that might occur during storage of the final product (U.S. Department of Agriculture Pathogen Modeling Program version 7.0). Simulation results indicated that the addition of L. sakei strains significantly decreased the simulated L. monocytogenes concentration of ready-to-eat fermented sausages at the time of consumption.