Topoisomerase VI senses and exploits both DNA crossings and bends to facilitate strand passage.

Topoisomerase VI senses and exploits both DNA crossings and bends to facilitate strand passage.

Elife. 2018 Mar 29;7:

Authors: Wendorff TJ, Berger JM

Abstract
Type II topoisomerases manage DNA supercoiling and aid chromosome segregation using a complex, ATP-dependent duplex strand passage mechanism. Type IIB topoisomerases and their homologs support both archaeal/plant viability and meiotic recombination. Topo VI, a prototypical type IIB topoisomerase, comprises two Top6A and two Top6B protomers; how these subunits cooperate to engage two DNA segments and link ATP turnover to DNA transport is poorly understood. Using multiple biochemical approaches, we show that Top6B, which harbors the ATPase activity of topo VI, recognizes and exploits the DNA crossings present in supercoiled DNA to stimulate subunit dimerization by ATP. Top6B self-association in turn induces extensive DNA bending, which is needed to support duplex cleavage by Top6A. Our observations explain how topo VI tightly coordinates DNA crossover recognition and ATP binding with strand scission, providing useful insights into the operation of type IIB topoisomerases and related meiotic recombination and GHKL ATPase machineries.

PMID: 29595473 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader https://ift.tt/2IfkJua

Polysulfide-triggered fluorescent indicator suitable for super-resolution microscopy and application in imaging.

Related Articles

Polysulfide-triggered fluorescent indicator suitable for super-resolution microscopy and application in imaging.

Chem Commun (Camb). 2018 Mar 28;:

Authors: A AH, Sreedharan S, Ali F, Smythe CG, Thomas JA, Das A

Abstract
A new physiologically benign and cell membrane permeable BODIPY based molecular probe, MB-Sn, specifically senses intracellular hydrogen polysulfides (H2Sn, n > 1) localized in the endoplasmic reticulum. This reagent is suitable for mapping the intracellular distribution of H2Sn by wide-field as well as super-resolution Structured Illumination Microscopy (SIM).

PMID: 29589001 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader https://ift.tt/2J3mEmJ

Evolution of dietary preferences and the innate urge to heal: Drug discovery lessons from Ayurveda.

Related Articles

Evolution of dietary preferences and the innate urge to heal: Drug discovery lessons from Ayurveda.

J Ayurveda Integr Med. 2018 Mar 22;:

Authors: Shrungeswara AH, Unnikrishnan MK

Abstract
Highly specialized and functionally integrated cognitive systems facilitate hedonistic and healthy food preferences. Guided by survival needs, flavor preferences not only select safe, nutritious dietary components, but also those with negligible calorific value but significant health benefits, for example, spices. Feeding behavior, both innate and acquired, is guided not only by taste receptors on the tongue but also visceral organs. The gustatory cortex receives information from all senses, not just taste, suggesting multiple checkpoints in predicting and evaluating healthy foods. Ayurvedic interpretation of 'rasa' as chemistry is compatible with medicinal value of diets because, taste and odor are chemosensory perceptions. As flavor and taste are linked to the chemical structure of compounds, taste might offer clues about pharmacological activity. Ayurvedic idea of vipaka, or post digestive perception of taste, recognizes the extended role of taste receptors beyond the tongue and stretching into the viscera. Ayurvedic wisdom is consistent with evolutionary guideposts that suggest three successive stages of nutritional appraisal: before, during, and after ingesting food. While olfaction induces affinity or revulsion even before ingestion, gustatory receptors on the tongue evaluates nutritional value upon contact, and the chemoreceptors in the deeper metabolic systems probably pronounce the final verdict on the nutritive and health benefits of ingested substances. Alliesthesia, neophobia, and the extreme variation in human T2R genes (coding for bitterness receptors) illustrate the importance of adaptive learning of dietary preferences. These evolutionary clues are compatible with the Ayurvedic principle of 'rasa', in facilitating the process of drug discovery.

PMID: 29576440 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader https://ift.tt/2pNymdx

Parasite Tolerance and Host Competence in Avian Host Defense to West Nile Virus.

Parasite Tolerance and Host Competence in Avian Host Defense to West Nile Virus.

Ecohealth. 2018 Mar 22;:

Authors: Burgan SC, Gervasi SS, Martin LB

Abstract
Competence, or the propensity of a host to transmit parasites, is partly underlain by host strategies to cope with infection (e.g., resistance and tolerance). Resistance represents the ability of hosts to prevent or clear infections, whereas tolerance captures the ability of individuals to cope with a given parasite burden. Here, we investigated (1) whether one easy-to-measure form of tolerance described well the dynamic relationships between host health and parasite burden, and (2) whether individual resistance and tolerance to West Nile virus (WNV) were predictable from single cytokine measures. We exposed house sparrows (HOSP) to WNV and measured subsequent changes in host performance, viral burden, and cytokine expression. We then used two novel approaches (one complex, one simpler) to estimate tolerance within-individual HOSP using four separate host performance traits. We lastly investigated changes in the expression of pro-inflammatory cytokine interferon-γ (IFN-γ) and anti-inflammatory cytokine interleukin-10 (IL-10). Both approaches to estimating tolerance were equivalent among WNV-infected HOSP; thus, an easy-to-measure tolerance estimation may be successfully applied in field studies. Constitutive expression of IFN-γ and IL-10 were predictive of resistance and tolerance to WNV, implicating these cytokines as viable biomarkers of host competence to WNV.

PMID: 29569179 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader https://ift.tt/2INOymP

The Role of the Sucrose-Responsive IR60b Neuron for Drosophila melanogaster: A Hypothesis.

The Role of the Sucrose-Responsive IR60b Neuron for Drosophila melanogaster: A Hypothesis.

Chem Senses. 2018 Mar 13;:

Authors: Szyszka P, Galizia CG

Abstract
In a recent paper, Joseph and colleagues (Joseph et al., 2017) have characterized an IR60b receptor-expressing neuron in Drosophila. They showed that it responds to sucrose and serves to limit sucrose consumption, and proposed that it may thereby act to prevent overfeeding. Here, we propose an alternative hypothesis for the functional role of sucrose feeding control, and for how this limitation of sucrose uptake is accomplished. Adult fruit flies feed by excreting saliva onto the food, and imbibing the predigested liquefied food, or by filling the crop, where the food is predigested. Enzymes in the saliva hydrolyze starch and disaccharides into absorbable monosaccharides. Premature ingestion into the midgut would not give the enzymes in the saliva enough time to predigest the food. Thus, IR60b neurons might serve as a sensor to monitor the digestive state of external food or crop content: when disaccharides (sucrose) concentration is high, ingestion to the gut is inhibited, keeping a low concentration of starch and disaccharides in the midgut.

PMID: 29546407 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2FKqTpC

Re-test reliability of gustatory testing and introduction of the sensitive Taste-Drop-Test.

Re-test reliability of gustatory testing and introduction of the sensitive Taste-Drop-Test.

Chem Senses. 2018 Mar 12;:

Authors: Fjaeldstad A, Niklassen A, Fernandes H

Abstract
The sense of taste holds a key integrate role in assessing the flavour of food before swallowing is initiated. If the expectations for taste are not met, palatability and pleasure of the food can decrease. In patients suffering from taste disorders, this may impair appetite and nutritional state. Testing gustatory function can be important for diagnostics and assessment of treatment effects. However, the gustatory tests applied are required to be both sensitive and reliable.In this study, we investigate the re-test validity of popular Taste Strips gustatory test for gustatory screening. Furthermore, we introduce a new sensitive Taste-Drop-Test, which was found to be superior for detecting a more accurate measure of tastant sensitivity.

PMID: 29538619 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2FHwF7b

Visual-olfactory Interactions: Bimodal Facilitation and Impact on the Subjective Experience.

Visual-olfactory Interactions: Bimodal Facilitation and Impact on the Subjective Experience.

Chem Senses. 2018 Mar 08;:

Authors: Amsellem S, Höchenberger R, Ohla K

Abstract
Odors are inherently ambiguous and therefore susceptible to redundant sensory as well as context information. The identification of an odor object relies largely on visual input. Thus far, it is unclear whether visual and olfactory stimuli are indeed integrated at an early perceptual stage and which role the congruence between the visual and olfactory inputs plays. Previous studies on visual-olfactory interaction used either congruent or incongruent information, leaving it open whether nuances of visual-olfactory congruence shape perception differently. We aimed to answer 1) whether visual-olfactory information is integrated at early stages of processing, 2) whether visual-olfactory congruence is a gradual or dichotomous phenomenon, and 3) whether visual information influences bimodal stimulus evaluation and odor identity. We found a bimodal RT speedup that is consistent with parallel processing according to race models. Subjectively, pleasantness of bimodal stimuli increased with increasing congruence, and orange images biased odor composition toward orange. Visual-olfactory congruence was perceived in gradual and distinct categories, consistent with the notion that congruence is a gradual phenomenon. Together, the data provide evidence for bimodal facilitation consistent with parallel processing of the visual and olfactory stimuli, and that visual-olfactory interactions influence various levels of the subjective experience.

PMID: 29528380 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2tIFfBc

Improved Dose-Response Relationship of (+)-Discodermolide-Taxol Hybrid Congeners.

Related Articles

Improved Dose-Response Relationship of (+)-Discodermolide-Taxol Hybrid Congeners.

J Nat Prod. 2018 Mar 09;:

Authors: Nadaradjane C, Yang CH, Rodriguez-Gabin A, Ye K, Sugasawa K, Atasoylu O, Smith AB, Horwitz SB, McDaid HM

Abstract
(+)-Discodermolide is a microtubule-stabilizing agent with potential for the treatment of taxol-refractory malignancies. (+)-Discodermolide congeners containing the C-3'-phenyl side chain of taxol (paclitaxel) were synthesized based on computational docking models predicting this moiety would fill an aromatic pocket of β-tubulin insufficiently occupied by (+)-discodermolide, thereby conferring improved ligand-target interaction. It was recently demonstrated, however, that the C-3'-phenyl side chain occupied a different space, instead extending toward the M-loop of β-tubulin, where it induced a helical conformation, hypothesized to improve lateral contacts between adjacent microtubule protofilaments. This insight led us to evaluate the biological activity of hybrid congeners using a panel of genetically diverse cancer cell lines. Hybrid molecules retained the same tubulin-polymerizing profile as (+)-discodermolide. Since (+)-discodermolide is a potent inducer of accelerated senescence, a fate that contributes to drug resistance, congeners were also screened for senescence induction. Flow cytometric and transcriptional analysis revealed that the hybrids largely retained the senescence-inducing properties of (+)-discodermolide. In taxol-sensitive cell models, the congeners had improved dose-response parameters relative to (+)-discodermolide and, in some cases, were superior to taxol. However, in cells susceptible to senescence, EMax increased without concomitant improvements in EC50 such that overall dose-response profiles resembled that of (+)-discodermolide.

PMID: 29522336 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2FMxIpJ

Characterization of the relationships between sleep duration, quality, architecture and chemosensory function in non-obese females.

Related Articles

Characterization of the relationships between sleep duration, quality, architecture and chemosensory function in non-obese females.

Chem Senses. 2018 Mar 07;:

Authors: Szczygiel EJ, Cho S, Tucker RM

Abstract
Little is known about the relationship between sleep and chemosensation. The purpose of this study was to characterize the relationship between chemosensory function and sleep duration, quality and architecture. A total of 56 non-obese (BMI<30 kg/m2) female participants who denied having diagnosed sleep disorders completed testing. Sleep was measured for two nights using a single-channel (A1-A2) electroencephalogram-(EEG) (Zmachine). Sweet taste threshold and preference as well as olfactory threshold, recognition ability, and pleasantness ratings were evaluated. Sweet taste preference was correlated with total sleep time (TST) (P=0.0074) as well as with the sum of rapid eye movement (REM) and stage N3/slow wave sleep (SWS) duration (P=0.0008). Participants who slept more than the average TST or more than the average REM+SWS time preferred lower concentrations of sweetness (P=0.041, 0.049, respectively), than those whose sleep times fell below the means. Multiple linear regression revealed that REM and SWS predicted approximately 18% of the variance of sweet taste preference. These findings suggest that scientific and consumer studies related to sweet preference might benefit from screening participants for short sleep duration prior to testing.

PMID: 29522075 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2FC7BP5

Preoperative Lund-Mackay computed tomography score is associated with preoperative symptom severity and predicts quality-of-life outcome trajectories after sinus surgery.

Related Articles

Preoperative Lund-Mackay computed tomography score is associated with preoperative symptom severity and predicts quality-of-life outcome trajectories after sinus surgery.

Int Forum Allergy Rhinol. 2018 Mar 08;:

Authors: Brooks SG, Trope M, Blasetti M, Doghramji L, Parasher A, Glicksman JT, Kennedy DW, Thaler ER, Cohen NA, Palmer JN, Adappa ND

Abstract
BACKGROUND: Disagreement exists about the relationship between Lund-Mackay CT scores (LMCTS) and quality-of-life outcome (QoL) measures. We investigated whether preoperative LMCTS are associated with preoperative QoL, and whether LMCTS is predictive of postoperative QoL outcomes in chronic rhinosinusitis (CRS) patients.
METHODS: Adult patients with medically recalcitrant CRS (n = 665) were enrolled in a prospective, observational cohort study. Preoperative LMCTS and pre- and postoperative self-reported QoL outcomes (22-item Sino-Nasal Outcomes Test [SNOT-22]) were collected and evaluated over 12 months. Five hundred sixty-eight patients met the inclusion criteria. Longitudinal linear mixed-effects modeling was used to investigate the effect of LMCTS on QoL after functional endoscopic sinus surgery (FESS).
RESULTS: Preoperative LMCTS were significantly associated with preoperative SNOT-22 scores (p < 0.01) and postoperative SNOT-22 scores (p < 0.001), driven by Extranasal and Rhinologic subdomains of the QoL questionaire. Patients in the lowest preoperative LMCTS quartile had the lowest mean change in SNOT-22 scores at 12 months (16.8 points; 95% confidence interval [CI], 12.2-21.3). Patients in the second and third lowest preoperative LMCTS quartiles had mean changes at 12 months of 21.1 points (95% CI, 16.7-25.4) and 23.1 points (95% CI, 18.3-27.9). Patients in the highest preoperative LMCTS quartile had the greatest improvement in SNOT-22 scores after FESS (29.9 points; 95% CI, 24.9-34.8). The difference in QoL change at 12 months between the highest and lowest preoperative LMCTS quartiles was 13.1 points (95% CI, 6.0-20.2; p < 0.001).
CONCLUSION: Our study demonstrates that preoperative LMCTS correlate with preoperative extranasal and rhinologic symptom severity and that the LMCTS is an indicator of postsurgical QoL outcomes for medically recalcitrant chronic rhinosinusitis patients in a large tertiary otolaryngology setting.

PMID: 29517156 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2oZNmDK

The Chemical Sensitivity and Electrical Activity of Individual Olfactory Sensory Neurons to a Range of Sex Pheromones and Food Odors in the Goldfish.

Related Articles

The Chemical Sensitivity and Electrical Activity of Individual Olfactory Sensory Neurons to a Range of Sex Pheromones and Food Odors in the Goldfish.

Chem Senses. 2018 Mar 03;:

Authors: Sato K, Sorensen PW

Abstract
Although it is well established that the olfactory epithelium of teleost fish detects at least 6 classes of biologically-relevant odorants using five types of olfactory sensory neurons (OSNs), little is understood about the specificity of individual OSNs and thus how they encode identity of natural odors. In this study we used in vivo extracellular single-unit recording to examine the odor-responsiveness and physiological characteristics of 109 individual OSNs in mature male goldfish to a broad range of biological odorants including feeding stimuli (amino acids, polyamines, nucleotides), sex pheromones (sex steroids, prostaglandins) and a putative social cue (bile acids). Sixty-one OSNs were chemosensitive, with over half of these (36) responding to amino acids, 7 to polyamines, 7 to nucleotides, 5 to bile acids, 9 to prostaglandins, and 7 to sex steroids. Approximately a quarter of the amino acid-sensitive units also responded to polyamines or nucleotides. Three of 6 amino acid-sensitive units responded to more than one amino acid compound, and 5 sex pheromone-sensitive units detected just one sex pheromone. While pheromone-sensitive OSNs also responded to the adenylyl cyclase activator, forskolin, amino acid-sensitive OSNs responded to either forskolin or a phospholipase C activator, imipramine. Most OSNs responded to odorants and activators with excitation. Our results suggest that pheromone information is encoded by OSNs specifically tuned to single sex pheromones and employ adenylyl cyclase, suggestive of a labeled-line organization, while food information is encoded by a combination of OSNs that use both adenylyl cyclase and phospholipase C and are often less specifically tuned.

PMID: 29514213 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2FA3CCr

Tastant-evoked Arc expression in the nucleus of the solitary tract and nodose/petrosal ganglion of the mouse is specific for bitter compounds.

Related Articles

Tastant-evoked Arc expression in the nucleus of the solitary tract and nodose/petrosal ganglion of the mouse is specific for bitter compounds.

Chem Senses. 2018 Mar 05;:

Authors: Töle J, Stolzenburg A, Tyree SM, Stähler F, Meyerhof W

Abstract
Despite long and intense research, some fundamental questions regarding representation of taste information in the brain still remain unanswered. This might in part be due to shortcomings of the established methods that limit the researcher either to thorough characterization of few elements or analyze the response of the entirety of neurons to only one stimulus. To overcome these restrictions, we evaluate the use of the immediate early gene Arc as a neuronal activity marker in the early neural structures of the taste pathway, the nodose/petrosal ganglion (NPG) and the nucleus of the solitary tract (NTS). Responses of NPG and NTS neurons were limited to substances that taste bitter to humans and are avoided by mice. Arc expressing cells were concentrated in the rostromedial part of the dorsal NTS suggesting a role in gustatory processing. The use of Arc as a neuronal activity marker has several advantages, primarily the possibility to analyze the response of large numbers of neurons while using more than one stimulus makes Arc an interesting new tool for research in the early stages of taste processing.

PMID: 29514200 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2FKACuX

Nicotinic acetylcholine receptor (CHRN) expression and function in cultured human adult fungiform (HBO) taste cells.

Related Articles

Nicotinic acetylcholine receptor (CHRN) expression and function in cultured human adult fungiform (HBO) taste cells.

PLoS One. 2018;13(3):e0194089

Authors: Qian J, Mummalaneni S, Larsen J, Grider JR, Spielman AI, Özdener MH, Lyall V

Abstract
In rodents, CHRNs are involved in bitter taste transduction of nicotine and ethanol. Currently, it is not clear if CHRNs are expressed in human taste cells and if they play a role in transducing the bitter taste of nicotine and ethanol or in the synthesis and release of neurohumoral peptides. Accordingly, we investigated the expression and functional role of CHRNs in HBO cells. Using molecular techniques, we demonstrate that a subset of HBO cells express CHRNs that also co-express TRPM5, T1R3 or T2R38. Exposing HBO cells to nicotine or ethanol acutely or to nicotine chronically induced a differential increase in the expression of CHRN mRNA and protein in a dose- and time-dependent manner. Acutely exposing HBO cells to a mixture containing nicotine plus ethanol induced a smaller increase in CHRN mRNAs relative to nicotine or ethanol treatment alone. A subset of HBO cells responded to nicotine, acetylcholine and ATP with a transient increase in [Ca2+]i. Nicotine effects on [Ca2+]i were mecamylamine sensitive. Brain-derived neurotrophic factor (BDNF) protein was detected in HBO cells using ELISA. Acute nicotine exposure decreased BDNF in HBO cells and increased BDNF release in the medium. CHRNs were also detected in HEK293 cells by RT-PCR. Unlike HBO cells, CHRNs were localized in most of HEK293 cells and majority of HEK293 cells responded to nicotine and ethanol stimulation with a transient increase in [Ca2+]i. BDNF levels in HEK293 cells were significantly higher than in HBO cells but the nicotine induced release of BDNF in the media was a fraction of the BDNF cellular content. We conclude that CHRNs are expressed in TRPM5 positive HBO cells. CHRN mRNA expression is modulated by exposure to nicotine and ethanol in a dose- and time-dependent manner. Nicotine induces the synthesis and release of BDNF in HBO cells.

PMID: 29513745 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2Hpawes

Feminization of Male Brown Treesnake Methyl Ketone Expression via Steroid Hormone Manipulation.

Related Articles

Feminization of Male Brown Treesnake Methyl Ketone Expression via Steroid Hormone Manipulation.

J Chem Ecol. 2018 Feb;44(2):189-197

Authors: Parker MR, Patel SM, Zachry JE, Kimball BA

Abstract
Pheromones are useful tools for the management of invasive invertebrates, but have proven less successful in field applications for invasive vertebrates. The brown treesnake, Boiga irregularis, is an invasive predator that has fundamentally altered the ecology of Guam. The development of control tools to manage Boiga remains ongoing. Skin-based, lipophilic pheromone components facilitate mating in brown treesnakes, with females producing the same long-chain, saturated and monounsaturated (ketomonoene) methyl ketones known to function as pheromones in garter snakes, Thamnophis sirtalis. Boiga also express novel, diunsaturated methyl ketones (ketodienes) with a purported function as a sex pheromone. In our study, we implanted 17 β-estradiol in adult male brown treesnakes in order to manipulate methyl ketone expression as sex attractants, an effect that would mirror findings with garter snakes. Specifically, estrogen promoted production of two ketomonoenes, pentatriaconten-2-one and hexatriaconten-2-one, and suppressed production of one ketodiene, heptatriacontadien-2-one. In bioassays, estrogen-implanted males elicited tongue-flicking and chin rubbing behavior from unmanipulated males, though the responses were weaker than those elicited by females. On Guam, wild males exhibited greatest responses to whole female skin lipid extracts and only weak responses to the methyl ketone fractions from females and implanted males. Our results suggest that sex identity in brown treesnakes may be conferred by the ratio of ketomonoenes (female) to ketodienes (male) from skin lipids and may be augmented by a sex-specific endocrine signal (estradiol). However, a blend of long-chain methyl ketones alone is not sufficient to elicit maximal reproductive behaviors in male Boiga.

PMID: 29508108 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2FHKwhb

E-nose, e-tongue and e-eye for edible olive oil characterization and shelf life assessment: A powerful data fusion approach.

Related Articles

E-nose, e-tongue and e-eye for edible olive oil characterization and shelf life assessment: A powerful data fusion approach.

Talanta. 2018 May 15;182:131-141

Authors: Buratti S, Malegori C, Benedetti S, Oliveri P, Giovanelli G

Abstract
The aim of this work was to investigate the applicability of e-senses (electronic nose, electronic tongue and electronic eye) for the characterization of edible olive oils (extra virgin, olive and pomace) and for the assessment of extra virgin olive oil and olive oil quality decay during storage at different temperatures. In order to obtain a complete description of oil samples, physico-chemical analyses on quality and nutritional parameters were also performed. Data were processed by PCA and a targeted data processing flow-sheet has been applied to physico-chemical and e-senses dataset starting from data pre-processing introducing an innovative normalization method, called t0 centering. On e-senses data a powerful mid-level data fusion approach has been employed to extract relevant information from different analytical sources combining their individual contributions. On physico-chemical data, an alternative approach for grouping extra virgin olive oil and olive oil samples on the basis of their freshness was applied and two classes were identified: fresh and oxidized. A k-NN classification rule was developed to test the performance of e-senses to classify samples in the two classes of freshness and the average value of correctly classified samples was 94%. Results demonstrated that the combined application of e-senses and the innovative data processing strategy allows to characterize edible olive oils of different categories on the basis of their sensorial properties and also to follow the evolution during storage of extra-virgin olive oil and olive oil sensorial properties thus assessing the quality decay of oils.

PMID: 29501132 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2HpaeEo

Diurnal Variation of Sweet Taste Recognition Thresholds Is Absent in Overweight and Obese Humans.

Related Articles

Diurnal Variation of Sweet Taste Recognition Thresholds Is Absent in Overweight and Obese Humans.

Nutrients. 2018 Mar 02;10(3):

Authors: Sanematsu K, Nakamura Y, Nomura M, Shigemura N, Ninomiya Y

Abstract
Sweet taste thresholds are positively related to plasma leptin levels in normal weight humans: both show parallel diurnal variations and associations with postprandial glucose and insulin rises. Here, we tested whether this relationship also exists in overweight and obese (OW/Ob) individuals with hyperleptinemia. We tested 36 Japanese OW/Ob subjects (body mass index (BMI) > 25 kg/m²) for recognition thresholds for various taste stimuli at seven different time points from 8:00 a.m. to 10:00 p.m. using the staircase methodology, and measured plasma leptin, insulin, and blood glucose levels before each taste threshold measurement. We also used the homeostatic model assessment of insulin resistance (HOMA-IR) to evaluate insulin resistance. The results demonstrated that, unlike normal weight subjects, OW/Ob subjects showed no significant diurnal variations in the recognition thresholds for sweet stimuli but exhibited negative associations between the diurnal variations of both leptin and sweet recognition thresholds and the HOMA-IR scores. These findings suggest that in OW/Ob subjects, the basal leptin levels (~20 ng/mL) may already exceed leptin's effective concentration for the modulation of sweet sensitivity and that this leptin resistance-based attenuation of the diurnal variations of the sweet taste recognition thresholds may also be indirectly linked to insulin resistance in OW/Ob subjects.

PMID: 29498693 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2FOMKLP

Associations between human fungiform papillae and responsiveness to oral stimuli: effects of individual variability, population characteristics, and methods for papillae quantification.

Related Articles

Associations between human fungiform papillae and responsiveness to oral stimuli: effects of individual variability, population characteristics, and methods for papillae quantification.

Chem Senses. 2018 Feb 27;:

Authors: Piochi M, Dinnella C, Prescott J, Monteleone E

Abstract
Fungiform papillae on human tongue are the proxy structures designated to oral stimuli detection and transduction. However, the role of their density (fungiform papillae/cm2) in explaining oral sensitivity is still controversial. While early studies generally found that the responsiveness to oral stimuli increased as the number of papillae increased, recent large-scale studies failed to confirm this finding.The present paper reviews relevant studies dealing with the relationship between fungiform papillae density and responsiveness to oral sensations including: fundamental tastes, 6-n-propyl-2-thiouracil (PROP) and sensations from trigeminal stimulation.Manual methods and automated methods for papillae detection and quantification are reviewed and their advantages and limitations highlighted. The main factors affecting fungiform papillae density and functionality (age, gender, pathologic impairments) are also considered. Possible bias related to methodological issues in counting technique (equipment used, area and location of the tongue to count, procedures to validate the count), population sample (demographics) and sensory response collection (threshold or supra-threshold stimuli, intensity scaling) are illustrated.The lack of information related to the variability in taste pores density and the possible impairments due to nerve damages, may obscure the relationship between FPD and oral responsiveness.

PMID: 29490007 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/2HuuxAj