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The introduction of iron ionic sites by metal exchange of defective homometallic nickel pyrazolate frameworks generates non-precious, Earth-abundant, first-row heterometallic Fe/Ni-pyrazolate frameworks. The Fe incorporation at the Ni nodes of the framework allows to control the hydrogen peroxide activation, minimizing its decomposition and O 2 liberation, occurring at the homometallic Ni nodes. The generation of Fe-OH reactive oxygen species at the heterometallic Fe/Ni nodes is demonstrated by the higher activity in the proof-of-concept oxidation of 1-phenylethanol to acetophenone in an aqueous medium., (© 2023 The Authors. ChemPlusChem published by Wiley-VCH GmbH.)

Spermatozoa require the capacitation, a series of biochemical events, to perform fertilization. Many toxic compounds can interfere in this process, including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), which belong to the perfluoroalkyl substances (PFAS). Since both substances are found in many everyday materials and are highly persistent, they accumulate in organisms where they have been associated with fertility problems. This study analyzes the effects of PFOS and PFOA on the functionality of boar spermatozoa, and changes in the plasma membrane (PM) during capacitation. The median lethal concentrations (LC50) of PFOS and PFOA were 460 and 1894 µM, respectively, while the mean inhibitory concentrations of capacitation (ICC50) were 274 µM and 1458 µM, respectively. The ICC50 of PFOA was insufficient to reduce the capacitation, but 950 µM (½ LC50) of PFOA and the ICC50 of PFOS significantly reduced the number of capacitated spermatozoa. PFOS and PFOA also impeded the progesterone (P4)-induced acrosomal reaction (iAR). These effects occur despite the accumulation of [Ca 2+ ] i under capacitating conditions. The accumulation of [Ca 2+ ] i produces saturation, which prevents its entry through ionophore A23187 and P4 in the presence of PFOS. Membrane potential (Emv) was deregulated. Both PFAS affected lipid membrane conductance mediated by valinomycin. The spermatozoa presented 49% and 47% of membrane dysfunction with PFOS and PFOA, respectively. By causing membrane damage, both substances prevented the release of cholesterol and altered the organization of membrane microdomains (MMDs). Data indicate that both PFAS caused alterations in PM functionality., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Cadmium (Cd) is a heavy metal related to a decrease in sperm parameters. The transit of spermatozoa through the epididymis is necessary to generate changes in the sperm membrane, such as the assembly of various carbohydrates that are added to the spermatazoan's surface to prepare it for successful fertilisation of the oocyte. No studies have yet analysed whether Cd alters the presence and distribution of these carbohydrates. We aimed to evaluate the changes induced by Cd in the distribution pattern of N-acetylglucosamine, sialic acid, mannose and fucose on the sperm membrane in the epididymis (e.g. caput, corpus, cauda) and if it alters the epididymal epithelium. Male Wistar pups were treated with Cd doses (0.125, 0.25 and 0.5mg/kg) on postnatal days 1-49. At postnatal day 90, they were humanely killed, sperm samples were obtained from the epididymis and tissue samples were taken for histological analysis. Cd concentrations in the blood and epididymis increased in proportion to the dose administered and decreased the serum testosterone levels and sperm quality. Histological analysis revealed alterations in the epithelium in all Cd-treated groups. Cd altered the distribution patterns of carbohydrates and fluorescence indices. All these alterations affected the structure and functioning of sperm.

Perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) are toxic and bioaccumulative, included in the Stockholm Convention's list as persistent organic pollutants. Due to their toxicity, worldwide distribution, and lack of information in spermatozoa physiology during pre-fertilization processes, the present study seeks to analyze the toxic effects and possible alterations caused by the presence of these compounds in boar sperm during the in vitro capacitation. The spermatozoa capacitation was performed in supplemented TALP-Hepes media and mean lethal concentration values of 460.55 μM for PFOS, and 1930.60 μM for PFHxS were obtained. Results by chlortetracycline staining showed that intracellular Ca 2+ patterns bound to membrane proteins were scarcely affected by PFOS. The spontaneous acrosome reaction determined by FITC-PNA was significantly reduced by PFOS and slightly increased by PFHxS. Both toxic compounds significantly alter the normal capacitation process from 30 min of exposure. An increase in ROS production was observed by flow cytometry and considerable DNA fragmentation by the comet assay. The immunocytochemistry showed a decrease of tyrosine phosphorylation in proteins of the equatorial and acrosomal zone of the spermatozoa head. In conclusion, PFOS and PFHxS have toxic effects on the sperm, causing mortality and altering vital parameters for proper sperm capacitation.

The surface of the spermatozoa is coated with glycoproteins the redistribution of which during in vitro capacitation plays a key role in the subsequent fertilization process. Lipid rafts are membrane microdomains involved in signal transduction through receptors and include or recruit specific types of proteins and glycoproteins. Few studies have focused on identifying glycoproteins resident in the lipid rafts of spermatozoa. Proteins associated with lipid rafts modify their localization during capacitation. The objective of the study was to identify the glycoproteins associated with lipid rafts of capacitated boar spermatozoa through a lectin-binding assay coupled to mass spectrometry approach. From the proteomic profiles generated by the raft proteins extractions, we observed that after capacitation the intensity of some bands increased while that of others decreased. To determine whether the proteins obtained from lipid rafts are glycosylated, lectin blot assays were performed. Protein bands with a good resolution and showing significant glycosylation modifications after capacitation were analyzed by mass spectrometry. The bands of interest had an apparent molecular weight of 64, 45, 36, 34, 24, 18 and 15 kDa. We sequenced the 7 bands and 20 known or potential glycoproteins were identified. According to us, for ten of them this is the first time that their association with sperm lipid rafts is described (ADAM5, SPMI, SPACA1, Seminal plasma protein pB1, PSP-I, MFGE8, tACE, PGK2, SUCLA2, MDH1). Moreover, LYDP4, SPAM-1, HSP60, ZPBP1, AK1 were previously reported in lipid rafts of mouse and human spermatozoa but not in boar spermatozoa. We also found and confirmed the presence of ACR, ACRBP, AWN, AQN3 and PRDX5 in lipid rafts of boar spermatozoa. This paper provides an overview of the glycosylation pattern in lipid rafts of boar spermatozoa before and after capacitation. Further glycomic analysis is needed to determine the type and the variation of glycan chains of the lipid rafts glycoproteins on the surface of spermatozoa during capacitation and acrosome reaction.

Niobium and antimony doped tin oxide loose-tubes decorated with Pt nanoparticles present outstanding mass activity and stability, exceeding those of a reference carbon-based electrocatalyst. Physico-chemical characterisation and in particular X-ray photoelectron spectroscopy demonstrate that this observation can be ascribed to the strong metal-support interaction promoting electroactivity and Pt anchoring on doped metal oxide supports.

SBA-15 type ordered silicas possessing amino groups attached onto their surfaces were prepared by using two different functionalization methodologies. These matrices were used for the cephalexin adsorption from aqueous solution and further kinetic study of its release into physiological solution. The materials were characterized by nitrogen adsorption/ desorption, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-Ray photoelectron spectrometry (XPS) and thermo analytical methods (TG/DSC). UV-visible spectroscopy at 262 nm was used for quantitative determination of cephalexin present in liquid media. Results reveal that drug adsorption capacities and the corresponding release profiles are dependent on the number of loaded amino groups and their location, which in turn is determined by the functionalization procedure used. It was concluded that amino post-functionalization could enhance long-term cephalexin delivery in comparison with co-functionalization procedure.