Marked increase in PROP taste responsiveness following oral supplementation with selected salivary proteins or their related free amino acids

The genetic predisposition to taste 6-n-propylthiouracil (PROP) varies among individuals and is associated with salivary levels of Ps-1 and II-2 peptides, belonging to the basic proline-rich protein family (bPRP). We evaluated the role of these proteins and free amino acids that selectively interact with the PROP molecule, in modulating bitter taste responsiveness. Subjects were classified by their PROP taster status based on ratings of perceived taste intensity for PROP and NaCl solutions. Quantitative and qualitative determinations of Ps-1 and II-2 proteins in unstimulated saliva were performed by HPLC-ESI-MS analysis. Subjects rated PROP bitterness after supplementation with Ps-1 and II-2, and two amino acids (L-Arg and L-Lys) whose interaction with PROP was demonstrated by (1)H-NMR spectroscopy. ANOVA showed that salivary levels of II-2 and Ps-1 proteins were higher in unstimulated saliva of PROP super-tasters and medium tasters than in non-tasters. Supplementation of Ps-1 protein in individuals lacking it in saliva enhanced their PROP bitter taste responsiveness, and this effect was specific to the non-taster group.(1)H-NMR results showed that the interaction between PROP and L-Arg is stronger than that involving L-Lys, and taste experiments confirmed that oral supplementation with these two amino acids increased PROP bitterness intensity, more for L-Arg than for L-Lys. These data suggest that Ps-1 protein facilitates PROP bitter taste perception and identifies a role for free L-Arg and L-Lys in PROP tasting

Gender and country differences in academic motivation, coping strategies, and academic burnout in a sample of Italian and Russian first-year university students

Background: The first year of university represents a challenging period that requires students to make significant investments in adaptive resources to face the new academic environment. The present study intends to contribute to the controversial discussion of gender differences in academic motivation, coping strategies, and academic burnout. This cross-sectional study examined above-mentioned constructs among first-year university students in a cross-cultural context. Methods: The sample consisted of 637 Italian and 496 Russian first-year university students (n = 1133), 40.3% of whom were females. The participants’ ages ranged from 17 to 23 years, with a mean age of 18.75 years (SD = 1.07). To assess academic motivation, coping strategies, and academic burnout, participants responded to the Academic Motivation Scale (AMS), the Coping Inventory for Stressful Situations (CISS), and the Maslach Burnout Inventory–Student Survey (MBI–SS) application. Results: The findings reveal gender and country differences in academic motivation, emotion and avoidance oriented coping strategies, and emotional exhaustion and expands previous studies in this educational area. Conclusion: Given the technical nature of the research topic, the target audience for our study is academic career guidance practitioners, who can apply the findings to the design of effective programmes aimed at improving positive academic goals and reducing the tendency to switch academic courses or abandon the university among first-year students

Time course of salivary protein responses to cranberry-derived polyphenol exposure as a function of PROP taster status

Astringency is a complex oral sensation, commonly experienced when dietary polyphenols interact with salivary proteins. Most astringent stimuli alter protein levels, which then require time to be replenished. Although it is standard practice in astringency research to provide breaks in between stimuli, there is limited consensus over the amount of time needed to restore the oral environment to baseline levels. Here we examined salivary protein levels after exposure to 20 mL of a model stimulus (cranberry polyphenol extract, 0.75 g/L CPE) or unsweetened cranberry juice (CJ), over a 10 min period. Whole saliva from healthy subjects (n = 60) was collected at baseline and after 5 and 10 min following either stimulus. Five families of proteins: basic proline-rich proteins (bPRPs); acidic proline-rich proteins (aPRPs); histatins; statherin; and S-type cystatins, were analyzed in whole saliva via HPLC-low resolution-ESI-IT-MS, using the area of the extracted ion current (XIC) peaks. Amylase was quantified via immunoblotting. In comparison to baseline (resting), both stimuli led to a rise in levels of aPRPs (p < 0.000) at 5 min which remained elevated at 10 min after stimulation. Additionally, an interaction of PROP taster status and time was observed, wherein super-tasters had higher levels of amylase in comparison to non-tasters after stimulation with CJ at both timepoints (p = 0.014–0.000). Further, male super-tasters had higher levels of bPRPs at 5 min after stimulation with both CJ and CPE (p = 0.015–0.007) in comparison to baseline. These data provide novel findings of interindividual differences in the salivary proteome that may influence the development of astringency and that help inform the design of sensory experiments of astringency

Thymosin Beta 4 may translocate from the cytoplasm in to the nucleus in HepG2 cells following serum starvation. An ultrastructural study

Due to its actin-sequestering properties, thymosin beta-4 (Tβ4) is considered to play a significant role in the cellular metabolism. Several physiological properties of Tβ4 have been reported;, however, many questions concerning its cellular function remain to be ascertained. To better understand the role of this small peptide we have analyzed by means of transmission immunoelectron microscopy techniques the ultrastructural localization of Tβ4 in HepG2 cells. Samples of HepG2 cells were fixed in a mixture of 3% formaldehyde and 0.1% glutaraldehyde in 0.1 M cacodylate buffer and processed for standard electron microscopic techniques. The samples were dehydrated in a cold graded methanol series and embedded in LR gold resin. Ultrathin sections were labeled with rabbit antibodies to Tβ4, followed by gold-labeled goat anti-rabbit, stained with uranyl acetate and bismuth subnitrate, observed and photographed in a JEOL 100S transmission electron microscope. High-resolution electron microscopy showed that Tβ4 was mainly restricted to the cytoplasm of HepG2 growing in complete medium. A strong Tβ4 reactivity was detected in the perinuclear region of the cytoplasmic compartment where gold particles appeared strictly associated to the nuclear membrane. In the nucleus specific Tβ4 labeling was observed in the nucleolus. The above electron microscopic results confirm and extend previous observations at light microscopic level, highlighting the subcellular distribution of Tβ4 in both cytoplasmic and nuclear compartments of HepG2 cells. The meaning of Tβ4 presence in the nucleolus is not on the best of our knowledge clarified yet. It could account for the interaction of Tβ4 with nucleolar actin and according with this hypothesis, Tβ4 could contribute together with the other nucleolar acting binding proteins to modulate the transcription activity of the RNA polymeras

Thymosin beta 4 expression in normal skin, colon mucosa and in tumor infiltrating mast cells

Mast cells (MCs) are metachromatic cells that originate from multipotential hemopoietic stem cells in the bone marrow. Two distinct populations of MCs have been characterized: mucosal MCs are tryptase-positive while mast cells in skin contain tryptase and chymase. We now show that a sub-population of MCs is highly immunoreactive for thymosin β4, as revealed by immunohistochemical analyses of normal skin, normal colon mucosa and salivary gland tumors. Four consecutive serial sections from each case were immunostained for thymosin β4 (Tβ4), chymase, tryptase and stained for toluidine blue. In skin biopsies, MCs showed a comparable immunoreactivity for Tβ4, chymase and tryptase. In normal colon mucosa the vast majority of mucosal MCs expressed a strong cytoplasmic immunoreactivity for tryptase and for Tβ4, in the absence of chymase reactivity. A robust expression of Tβ4 was detected in tumor-infiltrating and peritumoral mast cells in salivary gland tumors and breast ductal infiltrating carcinomas. Tumorinfiltrating MCs also showed a strong immunoreactivity for chymase and tryptase. In this paper, we first demonstrate that normal dermal and mucosal mast cells exhibit strong expression of thymosin β4, which could be considered a new marker for the identification of mast cells in skin biopsies as well as in human tumors. The possible relationship between the degree of Tβ4 expression in tumor-infiltrating mast cells and tumor behaviour warrants further consideration in future investigations

Saliva, a bodily fluid with recognized and potential diagnostic applications

Human whole saliva is a bodily fluid that can be obtained easily by noninvasive techniques. Specimens can be collected by the patient also at home in order to monitor health status and variations of several analytes of clinical interest. The contributions to whole saliva include secretions from salivary glands and, among others, from the gingival crevicular fluid that derives from the epithelial mucosa. Therefore, saliva is currently a relevant diagnostic fluid for many substances, including steroids, nonpeptide hormones, therapeutic drugs, and drugs of abuse. This review at first briefly describes the different contributions to whole saliva. A section illustrates the procedures for the collection, handling, and storage of salivary specimens. Another section describes the present use of whole saliva for diagnostic purposes and its specific utilization for the diagnosis of several local and systemic diseases. The final sections illustrate the future opportunities offered by various not conventional techniques with a focus on the most recent –omic investigations. It describes the various issues that have to be taken into account to avoid false positives and negatives, such as the strength of the experimental plan, the adequacy of the number of samples under study, and the proper choice of controls

Response to Cummins and Finaret (2019)

We thank Joseph Cummins and Amelia Finaret for their interest in our article (Comandini et al., 2019) and their insightful comments, which allowed us to further discuss the issue of age imprecision in nutritional studies. In this response, we aim to stress some points that interfere with the analysis of the three major concerns highlighted by the authors

Immunoreactivity of thymosin beta 4 in human foetal and adult genitourinary tract

Thymosin beta 4 (Tβ4) is a member of the beta-thymosins family, a family of peptides playing essential roles in many cellular functions. Our recent studies suggested Tβ4 plays a key role in the development of human salivary glands and the gastrointestinal tract. The aim of this study was to analyse the presence of Tβ4 in the human adult and foetal genitourinary tract. Immunolocalization of Tβ4 was studied in autoptic samples of kidney, bladder, uterus, ovary, testicle and prostate obtained from four human foetuses and four adults. Presence of the peptide was observed in cells of different origin: in surface epithelium, in gland epithelial cells and in the interstitial cells. Tβ4 was mainly found in adult and foetal bladder in the transitional epithelial cells; in the adult endometrium, glands and stromal cells were immunoreactive for the peptide; Tβ4 was mainly localized in the glands of foetal prostate while, in the adults a weak Tβ4 reactivity was restricted to the stroma. In adult and foetal kidney, Tβ4 reactivity was restricted to ducts and tubules with completely spared glomeruli; a weak positivity was observed in adult and foetal oocytes; immunoreactivity was mainly localized in the interstitial cells of foetal and adult testis. In this study, we confirm that Tβ4 could play a relevant role during human development, even in the genitourinary tract, and reveal that immunoreactivity for this peptide may change during postnatal and adult life

Spectral Analysis of the LMXB XTE J1810-189 with NICER Data

XTE J1810-189 is a Low-Mass X-ray Binary transient system hosting a neutron star, which underwent a three-month-long outburst in 2020. In order to study its spectral evolution during this outburst, we analysed all the available observations performed by NICER, in the 1-10 keV energy band. Firstly, we fitted the spectra with a thermal Comptonisation model. Our analysis revealed the lack of a significant direct emission from a black-body-like component, therefore we calculated the optical depth of the Comptonising region, deriving an upper limit of 4.5, which suggests the presence of a moderately thick corona. We also attempted to fit the spectrum with an alternative model, i.e. a cold Comptonised emission from a disc and a direct thermal component from the neutron star, finding a similarly good fit. The source did not enter a full high luminosity/soft state throughout the outburst, with a photon index ranging from 1.7 to 2.2, and an average unabsorbed flux in the 1-10 keV band of 3.6x10^(-10) erg cm^(-2) s^(-1). We searched for the presence of Fe K-shell emission lines in the range 6.4-7 keV, significantly detecting a broad component only in a couple of observations. Finally, we conducted a time-resolved spectral analysis of the detected type-I X-ray burst, observed during the outburst, finding no evidence of a photospheric radius expansion. The type-I burst duration suggests a mix of H/He fuel.Comment: 11 pages, 8 figures, accepted for publication on MNRA