Bioprospecting of a Metschnikowia pulcherrima Indigenous Strain for Chasselas Winemaking in 2022 Vintage.

Interest in Metschnikowia (M.) pulcherrima is growing in the world of winemaking. M. pulcherrima is used both to protect musts from microbial spoilage and to modulate the aromatic profile of wines. Here, we describe the isolation, characterization, and use of an autochthonous strain of M. pulcherrima in the vinification of Chasselas musts from the 2022 vintage. M. pulcherrima was used in co-fermentation with Saccharomyces cerevisiae at both laboratory and experimental cellar scales. Our results showed that M. pulcherrima does not ferment sugars but has high metabolic activity, as detected by flow cytometry. Furthermore, sensory analysis showed that M. pulcherrima contributed slightly to the aromatic profile when compared to the control vinifications. The overall results suggest that our bioprospecting strategy can guide the selection of microorganisms that can be effectively used in the winemaking process.

Attraction of Frankliniella occidentalis Females towards the Aggregation Pheromone Neryl (S)-2-Methylbutanoate and Kairomones in a Y-Olfactometer.

An understanding of insect olfaction allows for more specific alternative methods of pest control. We evaluated the responses of the western flower thrips (WFT, Frankliniella occidentalis) in a Y-olfactometer to estimate gas-phase concentrations of the aggregation pheromone neryl (S)-2-methylbutanoate and known kairomones such as methyl isonicotinate, (S)-(-)-verbenone, and p-anisaldehyde. The gas-phase concentrations of these compounds were obtained from the release rates measured in dynamic headspace cells. The compounds were collected from the headspace using dried solid-phase extraction (SPE) cartridges and analyzed with a triple quadrupole GC-MS/MS. We observed that the aggregation pheromone significantly attracted WFT females at doses of 10 and 100 µg, whereas methyl isonicotinate and p-anisaldehyde significantly attracted WFT females at the highest dose. Verbenone did not produce any significant results. A completely different picture was obtained when the gas-phase concentrations were considered. The minimal gas-phase concentrations of the pheromone required to attract WFT females was 0.027 ng/mL, at least 100 times lower than that of the other two compounds. The relevance and implications of our results are discussed in light of the insect's biology and pest management methods.

Simulating latrine conditions to assess perfume performance against malodour.

To evaluate perfume performance in toilets, we built model toilets in which critical factors such as background malodour, climate, and airflow were controlled. The models were equipped with an odour generator that injected hydrogen sulfide, methyl mercaptan, butyric acid, para-cresol, and indole, allowing us to accurately and reliably reconstitute toilet malodour headspace. The malodorant concentrations matched the quantitative headspace analysis performed in African and Indian toilets. The toilet malodour headspace performance was validated by chemical and sensory analysis. Olfactory stimuli were presented to participants in different simulated climates to assess the effect of climate on the perception of odours. The sensory data show that increasing temperature and humidity decreased the intensity ratings of odours without altering their quality. Perfume can be delivered in these toilets by forced evaporation to control the headspace concentration, or by delivery systems such as cellulosic pads, liquids, and powders. Our experimental set-up allowed us to establish dose-response curves to assess the performance of a perfume in reducing toilet malodour and increasing perceived pleasantness.

Identification of Hydrogen Disulfanes and Hydrogen Trisulfanes in H2S Bottle, in Flint, and in Dry Mineral White Wine.

Through the accidental contamination of a gas cylinder of H2S, the importance of polysulfanes for flint, gun powder, and match odors was discovered. The hydrogen disulfane was prepared from disulfanediylbis[methyl(diphenyl)silane], and its odor descriptor was evaluated in the gas phase from a gas chromatograph coupled to an olfaction port. The occurrence of this compound in flint and pebbles was confirmed by analyses after derivatization with pentafluorobromobenzene. The occurrence of this sulfane was also confirmed in two dry white Swiss Chasselas wines, sorted by a large-scale sensory analysis from 80 bottles and evaluated by 62 wine professionals. The occurrence of disulfane was confirmed for the two wines described as the most mineral. Polysulfane comprises a class of compounds contributing to the flint odor and that may contribute to the wine mineral odor descriptor. Due to the high volatility and instability pure HSSH was not isolated but kept in solution and its odor profile was described by gas chromatography coupled to an olfaction port as flint, matches, and fireworks with a higher odor intensity compared to H2S.

Quantitative headspace analysis of selected odorants from latrines in Africa and India.

This analytical investigation focuses on the quantification of odorant molecules in the headspace of latrines. Hydrogen sulfide and methyl mercaptan were derivatized under a more stable N-ethyl maleimide conjugate. Since the amount of odorant molecules is very low in the gas phase, we developed a method that had two steps of concentration. The first step consisted of the accumulation of volatiles in buffered water by bubbling 350 L of air in a bottle. The second step consisted of loading the water on a 1 g solid-phase extraction cartridge, shipping it to our laboratories, and desorbing with Et2O, which achieved a total concentration factor of 3.5 × 10(6). The acidification of the water phase gave us access to the acids, and an additional bottle containing an acidic ion-exchange resin gave us access to trimethyl amine. The limits of quantification in the gas phase were 8.7 × 10(-4) µg/L air for hydrogen sulfide, 1 × 10(-4) µg/L air for methyl mercaptan, 1 × 10(-3) µg/L air for butyric acid, 1 × 10(-4) µg/L air for p-cresol, 1 × 10(-5) µg/L air for indole, and 1 × 10(-5) µg/L air for skatole. The system was calibrated by using olfactometers, which can deliver a precisely known quantity of volatiles into the air. We were able to quantify all compounds near their odor detection thresholds (ODTs). All ODTs were measured in our laboratory with the same olfactometry method. This allowed accurate and comparable ODT values for malodorant compounds from toilets.

Water vapour and heat combine to elicit biting and biting persistence in tsetse.

BACKGROUND: Tsetse flies are obligatory blood feeders, accessing capillaries by piercing the skin of their hosts with the haustellum to suck blood. However, this behaviour presents a considerable risk as landing flies are exposed to predators as well as the host's own defense reactions such as tail flicking. Achieving a successful blood meal within the shortest time span is therefore at a premium in tsetse, so feeding until replete normally lasts less than a minute. Biting in blood sucking insects is a multi-sensory response involving a range of physical and chemical stimuli. Here we investigated the role of heat and humidity emitted from host skin on the biting responses of Glossina pallidipes, which to our knowledge has not been fully studied in tsetse before. METHODS: The onset and duration of the biting response of G. pallidipes was recorded by filming movements of its haustellum in response to rapid increases in temperature and/or relative humidity (RH) following exposure of the fly to two airflows. The electrophysiological responses of hygroreceptor cells in wall-pore sensilla on the palps of G. pallidipes to drops in RH were recorded using tungsten electrodes and the ultra-structure of these sensory cells was studied by scanning and transmission electron microscopy. RESULTS: Both latency and proportion of tsetse biting are closely correlated to RH when accompanied by an increase of 13.1°C above ambient temperature but not for an increase of just 0.2°C. Biting persistence, as measured by the number of bites and the time spent biting, also increases with increasing RH accompanied by a 13.1°C increase in air temperature. Neurones in wall-pore sensilla on the palps respond to shifts in RH. CONCLUSIONS: Our results show that temperature acts synergistically with humidity to increase the rapidity and frequency of the biting response in tsetse above the levels induced by increasing temperature or humidity separately. Palp sensilla housing hygroreceptor cells, described here for the first time in tsetse, are involved in the perception of differences in RH.

An extended phase II trial of iodine-125 methylene blue for sentinel lymph node identification in women with breast cancer.

BACKGROUND: The aim of this study was to determine if an intraoperative injection of iodine-125-labeled methylene blue ((125)I-MB) is a sensitive and effective method for detecting SLNs in women with breast cancer. STUDY DESIGN: Sixty-two women were enrolled in an extended phase II trial using (125)I-MB to guide SLNB. All patients were anesthetized and then injected subcutaneously with 1 mCi (125)I-MB in the outer quadrant of the areola. RESULTS: Radioactivity was detected in the axilla within 3 to 5 minutes. Fifty-eight of 62 (94%) patients had SLNs detected during their procedure. Mean (±SD) number of SLNs per patient was 1.8 ± 1.3 (range 0 to 6). A total of 112 nodes were dissected from 58 women; 110 of these nodes were considered sentinel. One hundred and eight (98%) nodes were hot, 98 (89%) nodes were blue, and 96 (87%) nodes were both hot and blue. Two women had complications; 1 had superficial skin staining and 1 had a superficial skin slough. Both healed uneventfully. No allergic reactions were observed. No radioactive uptake in the thyroid was seen. CONCLUSIONS: Iodine-125-labeled methylene blue can be mixed and administered in the operating room, improving hospital efficiency. Patient satisfaction is higher with (125)I-MB than with the technetium 99m sulfur colloid procedure because (125)I-MB does not produce localized burning and other adverse reactions associated with the traditional method, and 125I-MB is administered with the patient under anesthesia. Iodine-125 emits a lower-energy gamma ray than technetium 99m, lowering the surgeon's radiation exposure. Iodine-125-labeled methylene blue SLN identification is safe, cost effective, and produces equivalent outcomes compared with the traditional technique, making it an attractive alternative.