Odd-even effect in peptide SAMs-competition of secondary structure and molecule–substrate interaction

Peptide-based self-assembled monolayers (SAMs) are well known to be crucial for biocompatible surface formation on inorganic substrates applied for implants, biosensors, or tissue engineering. Moreover, recently these bioinspired nanostructures are also considered particularly interesting for molecular electronics applications due to their surprisingly high conductance and thickness-independent capacitance, which make them a very promising element of organic field-effect transistors (OFETs). Our structural analysis conducted for a series of prototypic homooligopeptides based on glycine (Gly) with cysteine (Cys) as a substrate bonding group chemisorbed on Au and Ag metal substrates (GlynCys/Au(Ag), n = 1−9) exhibits the formation by these monolayers secondary structure close to β-sheet conformation with pronounced odd−even structural effect strongly affecting packing density and conformation of molecules in the monolayer, which depend on the length of molecules and the type of metal substrate. Our experiments indicate that the origin of these structural effects is related to the either cooperative or competitive relationship between the type of secondary structure formed by these molecules and the directional character of their chemical bonding to the metal substrate. The current analysis opens up the opportunity for the rational design of these biologically inspired nanostructures, which is crucial both for mentioned biological and electronic applications

Formation of self-assembled monolayers based on bioorganic molecules

Samoorganizujące się monowarstwy SAM cieszą się ogromną popularnością nie tylko ze względu na łatwość preparatyki, ale również ze względu na stosunkowo łatwą możliwość modyfikowania właściwości fizykochemicznych powierzchni, które determinują ich potencjalne zastosowania. Łączenie organicznych molekuł z metalicznymi podłożami pozwala na stworzenie materiałów hybrydowych o ściśle określonych i pożądanych właściwościach, szczególnie w ujęciu oczekiwanego przewrotu w zakresie diagnostyki i leczenia w dziedzinie medycyny. Tworzenie nanostruktur z wykorzystaniem molekuł pochodzenia biologicznego pozwala na zrozumienie sposobu tworzenia struktur białek, które jest istotne nie tylko z punktu widzenia prześledzenia sposobu w jaki powstało życie, ale również dla jego znacznego wydłużenia.Oligopeptydy składające się z cząsteczki cysteiny i wzrastającej liniowo liczby molekuł glicyny Cys(Gly)*n, n=0-9 zostały zaadsorbowane do metalicznych podłoży złota (Au) oraz srebra (Ag), w celu sprawdzenia sposobu, w jaki tworzą się struktury drugorzędowe peptydów przytwierdzonych do organicznych, metalicznych podłoży w porównaniu do ich natywnego środowiska w białkach, a także czy efekt ten zależy od zastosowanego podłoża. W tym celu wykorzystano powierzchniowe metody badania próbek: spektroskopię fotoelektronów emitowanych w wyniku wzbudzenia promieniowaniem X (XPS) oraz refleksyjno – absorpcyjną spektroskopię w podczerwieni (IRRAS).Self-assembled monolayers (SAMs) are of great interest not only for their simple preparation, but also due to relatively easy prospects of changing physicochemical properties of its surfaces, which establish their potential applications. Combining bioorganic molecules with metallic substrates allow for creating hybrid materials with specific and interesting properties which are desirable in terms of expected revolution in diagnostic and medical treatment. Biological molecules adsorption at surfaces provide gathering information of the basic biological structures at the nanometer scale. This knowledge is crucial not only to enquire on how did life arise on Earth, but also as a factor to extend it.The oligopeptide Cys(Gly)*n, based SAMs analyzed in this study consist of cysteine and linearly growing number of glycines units (n) ranging form n=0 to n=9. Monolayers have been deposited from a solution phase on either silver (Ag) or gold (Au) surfaces. The aim was compare secondary structure formation of such nanometer thin protein films on two different coinage substrates with protein structures known from their native biological environment. Chemical and structural informations have been obtained bytwo types of spectroscopy analysis X-ray Photoelectron Spectroscopy (XPS) and Infrared Reflection – Absorption Spectroscopy (IRRAS)

The utilization of the Atomic Force Microscopy in the evaluation of morphological and mechanical properties changes of the polymer based nanomaterials, in terms of ageing process.

W pracy opisano wyniki badań degradacji powierzchni próbek polietylenu oraz stworzonych na jego osnowie kompozytów z dodatkiem stabilizatora UV oraz nanocząstek MMT w funkcji czasu narażenia na promieniowanie świetlne. Główną wykorzystaną techniką była mikroskopia sił atomowych AFM pozwalająca na ocenę zmian parametrów morfologicznych i właściwości mechanicznych badanych powierzchni. Uzyskane dane zostały skonfrontowane z wynikami zmian kąta zwilżalności oraz analizy kolorymetrycznej.This work describes the results of the light radiation exposure caused surface degradation of the polyethylene material and its composites with added photostabilizer and MMT nanoparticles. The main used technique was atomic force microscopy (AFM), which allows to evaluate changes in morphological parameters and the mechanical properties of the surface. The obtained data were confronted with the results of the wetting angle measurements and discoloration analysis

Changes in the Sexual Behavior of Partners in Each Trimester of Pregnancy in Otwock in Polish Couples

The aim of this study was to improve knowledge regarding pregnant couples by assessing changes in their sexual behavior, the reasons for the frequency and forms of intercourse, and the self-sexuality of partners in each trimester of pregnancy. As a result, 100 couples were qualified to take part in the final study, with 100 men and 100 women examined at intervals equivalent to the trimesters of pregnancy. These women (n = 100) and men (n = 100) were partners. Each of the studied couples was assessed in the trimesters of pregnancy. A prospective examination was conducted based on the observation of the same people, which were heterosexual couples, throughout pregnancy. The data used in the study was obtained using Davies’ Sexual Satisfaction Scale (DSSS), as well as an original survey on the sexuality of people during pregnancy (SARSS). The survey allowed us to obtain sociodemographic (metrics) information along with information regarding the sexual activity, satisfaction, and sexual attraction of the partners. All questionnaire questions were answered in paper form. There was a statistically significant drop in sexual intercourse from the first trimester in the second and third trimesters. The frequency of masturbation increased in men and decreased in women. The most common cause of sexual abstinence during the pregnancy was cited as fear for the fetus by all genders. A statistical analysis indicated that the average overall scores of the DSSS for the examined women in the first trimester of pregnancy were statistically significantly higher than in the two subsequent trimesters (p < 0.05). Sexual satisfaction, measured through both DSSS and SARSS, was also strongly correlated with the level of satisfaction in the assessment of the partner relationship and with the sense of one’s own attractiveness (p < 0.05). Changes in sexual behavior and sexual problems are often exposed or worsened during a first pregnancy and can have negative impacts on a person and the future of relationships. Medical staff should be trained in the assessment of sexual difficulties in people during pregnancy, in order to conduct reliable education and increase the awareness of couples regarding sexual and reproductive health

The Structural Changes in the Membranes of Staphylococcus aureus Caused by Hydrolysable Tannins Witness Their Antibacterial Activity

Polyphenols, including tannins, are phytochemicals with pronounced antimicrobial properties. We studied the activity of two hydrolysable tannins, (i) gallotannin—1,2,3,4,5-penta-O-galloyl-β-D-glucose (PGG) and (ii) ellagitannin—1,2-di-O-galloyl-4,6-valoneoyl-β-D-glucose (dGVG), applied alone and in combination with antibiotics against Staphylococcus aureus strain 8324-4. We also evaluated the effect of these tannins on bacterial membrane integrity and fluidity and studied their interaction with membrane proteins and lipids. A correlation between the antimicrobial activity of the tannins and their membranotropic action depending on the tannin molecular structure has been demonstrated. We found that the antibacterial activity of PGG was stronger than dGVG, which can be associated with its larger flexibility, dipole moment, and hydrophobicity. In addition, we also noted the membrane effects of the tannins observed as an increase in the size of released bacterial membrane vesicles

Role of Cdx2 and cell polarity in cell allocation and specification of trophectoderm and inner cell mass in the mouse embryo

Genesis of the trophectoderm and inner cell mass (ICM) lineages occurs in two stages. It is initiated via asymmetric divisions of eight- and 16-cell blastomeres that allocate cells to inner and outer positions, each with different developmental fates. Outside cells become committed to the trophectoderm at the blastocyst stage through Cdx2 activity, but here we show that Cdx2 can also act earlier to influence cell allocation. Increasing Cdx2 levels in individual blastomeres promotes symmetric divisions, thereby allocating more cells to the trophectoderm, whereas reducing Cdx2 promotes asymmetric divisions and consequently contribution to the ICM. Furthermore, both Cdx2 mRNA and protein levels are heterogeneous at the eight-cell stage. This heterogeneity depends on cell origin and has developmental consequences. Cdx2 expression is minimal in cells with unrestricted developmental potential that contribute preferentially to the ICM and is maximal in cells with reduced potential that contribute more to the trophectoderm. Finally, we describe a mutually reinforcing relationship between cellular polarity and Cdx2: Cdx2 influences cell polarity by up-regulating aPKC, but cell polarity also influences Cdx2 through asymmetric distribution of Cdx2 mRNA in polarized blastomeres. Thus, divisions generating inside and outside cells are truly asymmetric with respect to cell fate instructions. These two interacting effects ensure the generation of a stable outer epithelium by the blastocyst stage

Embryonic Environmental Niche Reprograms Somatic Cells to Express Pluripotency Markers and Participate in Adult Chimaeras

The phenomenon of the reprogramming of terminally differentiated cells can be achieved by various means, like somatic cell nuclear transfer, cell fusion with a pluripotent cell, or the introduction of pluripotency genes. Here, we present the evidence that somatic cells can attain the expression of pluripotency markers after their introduction into early embryos. Mouse embryonic fibroblasts introduced between blastomeres of cleaving embryos, within two days of in vitro culture, express transcription factors specific to blastocyst lineages, including pluripotency factors. Analysis of donor tissue marker DNA has revealed that the progeny of introduced cells are found in somatic tissues of foetuses and adult chimaeras, providing evidence for cell reprogramming. Analysis of ploidy has shown that in the chimaeras, the progeny of introduced cells are either diploid or tetraploid, the latter indicating cell fusion. The presence of donor DNA in diploid cells from chimaeric embryos proved that the non-fused progeny of introduced fibroblasts persisted in chimaeras, which is evidence of reprogramming by embryonic niche. When adult somatic (cumulus) cells were introduced into early cleavage embryos, the extent of integration was limited and only cell fusion-mediated reprogramming was observed. These results show that both cell fusion and cell interactions with the embryonic niche reprogrammed somatic cells towards pluripotency

Effects of Spherical and Rod-like Gold Nanoparticles on the Reactivity of Human Peripheral Blood Leukocytes

Gold nanoparticles (GNPs) are widely used in the technological and biomedical industries, which is a major driver of research on these nanoparticles. The main goal of this study was to determine the influence of GNPs (at 20, 100, and 200 μg/mL concentrations) on the reactivity of human peripheral blood leukocytes. Flow cytometry was used to evaluate the respiratory burst activity and pyroptosis in monocytes and granulocytes following incubation with GNPs for 30 and 60 min. Furthermore, the concentration of interleukin-1β (IL-1β) in human blood samples was assessed using enzyme-linked immunosorbent assay (ELISA) after their incubation with GNPs for 24 h. Under the conditions tested in the study, the GNPs did not significantly affect the production of reactive oxygen species in the granulocytes and monocytes that were not stimulated using phorbol 12-myristate 13-acetate (PMA) in comparison to the samples exposed to PMA (p p < 0.05). From our results, we conclude that the physicochemical properties of the nanoparticles, chemical composition, and the type of nanoparticles used in the unit, along with the unit and incubation time, influence the induced toxicity

Proteomic plasma profile of psoriatic patients

Psoriasis is a chronic, immune-mediated inflammatory skin disease with severe consequences for the whole organism. The lack of complete knowledge of the main factors predisposing an individual to the appearance of psoriatic lesions, has recently led to the search for modifications in biochemical pathways participating in the development of this disease. We therefore aimed to investigate changes in the plasma proteomic profile of patients with psoriasis.publishe