Real-life stressors, such as university examination, cause an increase in sympathetic activity of the nervous system innervating the heart, and thus an increase in heart rate (HR). Our study aimed to detect changes in heart rate variability (HRV) during different stages of an exam in a group of 90 healthy university students (30 males and 60 females), over 4 h of monitoring divided into 1 h before, 2 h during, and 1 h after the examination. HRV was significantly highest after the exam, indicating release from stress, as compared to before and during the examination when stress was observable. Undergraduate students in different academic years did not differ in terms of stress, indicating the absence of adaptation to exam procedures. However, HR and R-R interval after the exam showed significant difference between first year undergraduate studies and first year of a graduate program, indicating a higher degree of confidence in graduate students. Results also suggest that HRV in females is significantly lower than that in males before and after examination, despite men having greater sympathetic input. In conclusion, the results of our novel study assessing stress in real-time examination show important gender differences, and lack of adaptation with academic study year.

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Amphibia egg jelly coats are formed by components secreted along the oviduct. These secretion products overlay the oocytes as they pass along the different oviducal portions. Mucin type glycoproteins are the major constituents of the egg jelly coats. In this study, the O-linked carbohydrate chains of the jelly coats surrounding the eggs of Rana ridibunda were released by alkaline borohydride treatment. Fractionation of the mixture of O-linked oligosaccharidealditols was achieved by a combination of chromatographic techniques including gel-permeation chromatography, ion-exchange chromatography and high-performance liquid chromatography using an amino-bonded silica column. The primary structures of these O-glycans were determined by one-dimensional and two-dimensional 1 H-NMR spectroscopy and matrix-assisted laser-desorption-ionization-time-of flight mass spectrometry. 25 oligosaccharide structures, possessing a core consisting of Gal(b1±3)GalNAc-ol with or without branching through a GlcNAc residue linked (b1±6) to the GalNAc residue (core type 2 or core type 1, respectively) are described. The most representative antennae are:Gal(b1-3)GalNAc(a1-4)Gal(b1-4)Gal and GlcA(b1-3)Gal(b1-3)GalNAc. These results confirm the species-specific O-glycosylation of Amphibia oviducal mucins. The significance of this observation should be linked to a symbiotic role of carbohydrates involved in host±parasite interactions.Keywords: Amphibia; mucins; Rana ridibunda; NMR; carbohydrates.A characteristic feature of amphibia eggs is the presence of a water-insoluble gelatinous matrix, termed the jelly coat, surrounding the egg. Jelly coat layers are synthesized by specific regions of the oviduct and are sequentially deposited as the egg is transported toward the cloaca. Interest in these oviductally derived investments has centered on their obligatory participation in the early events of fertilization. The jelly coats are the first barrier for fertilizing sperm that must be passed through before reaching the egg plasma membrane. Thus, the jelly coats play a key role in the process of fertilization by facilitating adherence of the spermatozoa to the egg surface and by acting to block polyspermy [1±4].Mucin type glycoproteins have been shown to be the major components of this coat and implicated in important roles in fertilization. Of particular interest are several proposals suggesting the role of sugar chains as sperm receptors, due to the action of glycosidases or glycosyltransferases. Previous structural studies have demonstrated a remarkable species specificity in carbohydrate chains attached to the proteic axis of the oviducal mucins [5±11]. Consequently, these carbohydrate chains represent new phenotypic markers of amphibia species, and from a biological point of view, could be involved in species-specific gamete-recognition or in specific host±parasite interaction [12].Moreover, these structural analyses have led to the definition of several new glycosyltransferase activities reponsible for the structural species specificity. Acc...

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This study investigated the effect of the growth temperature (20 and 37 °C) of Escherichia coli strains isolated from pigs on their adhesion to stainless steel and polycarbonate. This study also evaluated the ability of the DLVO and XDLVO mathematical models to predict this adhesion. The rise of growth temperature from 20 to 37 °C significantly influenced the adhesion of studied E. coli strains. The data also underlined that the mathematical prediction did not fully match with the experimental bacterial adhesion to surfaces. Furthermore, results showed that the colistin-resistant and sensitive E. coli strains adhesion depends on the type of abiotic surface. Based on these results, the mathematical models are limited in the prediction of the bacterial adhesion to abiotic surfaces. The surface roughness is a major parameter of the bacterial adhesion and should be included in the future mathematical models predicting the bacterial adhesion.