Paula Costa

Abnormal methylation of imprinted genes in human sperm is associated with oligozoospermia

Genomic imprinting marks in the male germ line are already established in the adult germinal stem cell population. We studied the methylation patterns of H19 and MEST imprinted genes in sperm of control and oligozoospermic patients, by bisulphite genomic sequencing. We here report that 7 out of 15 (46.7%) patients with a sperm count below 10 x 10(6)/ml display defective methylation of H19 and/or MEST imprinted genes. In these cases, hypomethylation was observed in 5.54% (1.2-8.3%) and complete unmethylation in 2.95% (0-5.9%) of H19 clones. Similarly, for the CTCF-binding site 6, hypomethylation occurred in 4.8% (1.2-8.9%) and complete unmethylation in 3.7% (0-6.9%) of the clones. Conversely, hypermethylation occurred in 8.3% (3.8-12.2%) and complete methylation in 6.1% (3.8-7.6%) of MEST clones. Of the seven patients presenting imprinting errors, two had both H19 hypomethylation and MEST hypermethylation, whereas five displayed only one imprinted gene affected. The frequency of patients with MEST hypermethylation was highest in the severe oligozoospermia group (2/5 patients), whereas H19 hypomethylation was more frequent in the moderate oligozoospermia (2/5 patients). In all cases, global sperm genome methylation analysis (LINE1 transposon) suggested that defects were specific for imprinted genes. These findings could contribute to an explanation of the cause of Silver-Russell syndrome in children born with H19 hypomethylation after assisted reproductive technologies (ART). Additionally, unmethylation of the CTCF-binding site could lead to inactivation of the paternal IGF2 gene, and be linked to decreased embryo quality and birth weight, often associated with ART.

Pyrolysis of plastic wastes. 1. Effect of plastic waste composition on product yield

Abstract Accumulation of enormous amounts of plastic waste produced all over the world has negative implications on the environment. Pyrolysis of plastic waste could have an important role in converting this waste into economically valuable hydrocarbons, which can be used either as fuels or as feed stock in the petrochemical industry. End product yields and properties depend on the plastic waste composition. The presence of PE (polyethylene) increased alkane content, whilst PS (polystyrene) led to higher aromatic content in the end product. The presence of PP (polypropylene) favoured alkene formation. Therefore, both PS and PP increased the octane number of end product. Therefore, the desired end product can be obtained by adequate blending of plastic wastes.

Pyrolysis of plastic wastes: 2. Effect of catalyst on product yield

Abstract Thermolysis of plastic waste may have an important role in dealing with the enormous amounts of plastic waste produced all over the world, by decreasing their negative impact on the environment. This waste may be converted into economically valuable hydrocarbons, which can be used both as fuels and as feed stock in the petrochemical industry. End product yields and properties depend on the plastic waste composition. The presence of PE (polyethylene) increases alkane content, whilst PS (polystyrene) leads to higher aromatic content in the end product. The alkene formation benefited from the presence of PP (polypropylene). Although, the desired end products can be obtained by adequate blending of plastic wastes, it is not always technically or economically possible to obtain the quality required. The addition of a catalyst could not only improve the quality of products obtained, but could also enable the selectivity of a certain product to be achieved. To study the influence of several catalysts on product distribution, the average plastic waste composition existing in Portuguese municipal solid wastes (68% PE, 16% PP and 16% PS) was chosen. Unfortunately, the catalysts studied in this work, led to results similar to those obtained in their absence.

Identification of new breakpoints in AZFb and AZFc

Microdeletions in AZFa, AZFb and AZFc regions lead to different patterns of male infertility, from severe oligozoospermia to non-obstructive azoospermia. Intrachromosomal homologous recombination mechanisms were already identified in patients with simultaneous microdeletions in the AZFb and AZFc regions. Ten patients with atypical AZFb and AZFc deletion patterns were studied. The definition of those microdeletions and the fine characterization of the respective breakpoints were performed using sequence tagged sites/single nucleotide variants-PCR and DNA sequencing. Y-chromosome haplogroups were determined to establish a putative association with the patterns obtained. Seven deletion patterns were identified, P5/terminal (30%; 3/10), P5/P1 distal (20%; 2/10), IR4/distal-P2, IR2/proximal-P1, IR4/distal-P1, P4/terminal and complete AZFb/c deletion (10%; 1/10). Breakpoint sequence analysis suggests that only in one patient the P5/P1 distal deletion pattern was due to a homologous recombination mechanism. Sequence alignment of the other deletion patterns suggest that they have resulted from non-homologous recombination mechanisms.

AZFb microdeletions and oligozoospermia—which mechanisms?

OBJECTIVE To characterize the deletion patterns and its breakpoints in oligozoospermic patients presenting AZFb and AZFc microdeletions and to understand the recombination mechanisms underlying these microdeletions. DESIGN Case report. SETTING Genetics Department of Faculty of Medicine of Porto, Porto, Portugal. PATIENT(S) Two men with severe oligozoospermia and two men with nonobstructive azoospermia identified as having different AZFb+c deletion patterns via Y chromosome microdeletion analysis. INTERVENTION(S) Definition of microdeletions and the fine characterization of the respective breakpoints by sequence-tagged sites (STS) polymerase chain reaction (PCR) and single-nucleotide variant (SNV) PCR. MAIN OUTCOME MEASURE(S) Study of the fine structure of the Y-chromosome and discussion of the putative mechanisms involved in each microdeletion pattern. RESULT(S) From the four patients studied, three deletion patterns were identified: IR4/distal-P2 (25%; 1 of 4), P5/proximal-P1 (50%; 2 of 4), and P5/distal-P1 (25%; 1 of 4). Although severe oligozoospermia is normally associated with AZFc, a complete AZFb deletion was found in one case. CONCLUSION(S) Analysis of these patients has revealed a new putative region that may be involved in spermatogenesis conservation.

Naphthopyran-Based Silica Nanoparticles as New High-Performance Photoresponsive Materials

Hybrid nanomaterials based on the covalent grafting of silylated naphthopyrans (NPTs) onto silica nanoparticles (SiO2 NPs) were successfully prepared and studied as new photochromic materials. They were prepared by a two-step protocol consisting of (i) NPTs (derivatives from 2H-naphtho[1,2-b]pyran (2H-NPT) and 3H-naphtho[2,1-b]pyran (3H-NPT)) silylation by a microwave-assisted reaction between hydroxyl-substituted NPTs and 3-(triethoxysilyl)propyl isocyanate, followed by (ii) covalent post-grafting onto SiO2 NPs. In order to study the role of the silylation step, the analogous non-silylated nanomaterials were also prepared by direct adsorption of NPTs. The characterization techniques confirmed the successful NPTs silylation and subsequent grafting to SiO2 NPs. All SiO2-based nanomaterials revealed photoswitching behavior, following a biexponential decay. The SiO2 NPs functionalized with silylated 3H-NPTs (SiO2@S3 and SiO2@S4) presented the most promising photochromic properties, showing fast coloration/decoloration kinetics (coloring in 1 min under UV irradiation and fading in only 2 min) and high values of total color difference (ΔE*ab = 30-50). Also, the 2H-NPTs-based SiO2 NPs (SiO2@S1 and SiO2@S2) presented fast coloration and good color contrasts (ΔE*ab = 54), but slower fading kinetic rates, taking more than 2 h to return to their initial color. In contrast, the SiO2 NPs functionalized with non-silylated NPTs (SiO2@1 and SiO2@3) showed weaker color contrasts (ΔE*ab = 6-10) and slower fading kinetics, proving that the NPT silylation step was crucial to enhance the photochromic behavior of SiO2 NPs based on NPTs. Furthermore, the silylated-based nanomaterials showed good photostability upon prolonged UV light exposure, keeping their photochromic performance unchanged for at least 12 successive UV/dark cycles, anticipating interesting technological applications in several areas.

Direct access to polycyclic peripheral diepoxy-meso-quinone derivatives from acene catalytic oxidation

The unprecedented epoxidation on the peripheral positions of tetracene and pentacene with hydrogen peroxide-urea adduct catalyzed by the metalloporphyrin [Mn(TDCPP)Cl] is reported under mild conditions, affording the direct polyfunctionalization of the acenes to anti-diepoxy-meso-quinone derivatives.

Low Erythropoietin Production in Familial Amyloidosis TTR V30M Is Not Related with Renal Congophilic Amyloid Deposition

Background: Anemia with low serum erythropoietin (EPO) is common in Portuguese transthyretin V30M amyloid polyneuropathy (FAP). Low EPO production can be observed before clinical disease. Renal amyloidosis is observed in FAP, mainly in the medulla. Renal manifestations correlate with glomerular and vascular involvement, but not with tubulointerstitial deposition. To evaluate the potential role of renal amyloid deposits in the genesis of the EPO defect in FAP, we analyzed the renal biopsies of 12 patients (5 males, 7 females, aged from 29 to 54 years) with a clinical evolution varying from 3 to 12 (mean 5.4 ± 2.8) years. Methods: Formalin-fixed, paraffin-embedded sections of renal biopsies were stained by Congo red. Amyloid deposits were assessed by a semiquantitative method based on the percentage of amyloid deposition in each renal structure. Hemoglobin, creatinine, urea, EPO and proteinuria were concomitantly evaluated and correlated with the pathological findings. Results: Renal amyloid deposits were observed in all biopsies analyzed, independently of the neuropathy score. Low serum EPO levels were not related with either the amount of amyloid deposition or the renal clinical manifestations. Conclusion: Impairment of EPO production in FAP is not directly related to renal amyloid deposits and more studies are needed to clarify this question.

Screen-Printed Photochromic Textiles through New Inks Based on SiO2@naphthopyran Nanoparticles

Photochromic silica nanoparticles (SiO2@NPT), fabricated through the covalent immobilization of silylated naphthopyrans (NPTs) based on 2H-naphtho[1,2-b]pyran (S1, S2) and 3H-naphtho[2,1-b]pyran (S3, S4) or through the direct adsorption of the parent naphthopyrans (1, 3) onto silica nanoparticles (SiO2 NPs), were successfully incorporated onto cotton fabrics by a screen-printing process. Two aqueous acrylic- (AC-) and polyurethane- (PU-) based inks were used as dispersing media. All textiles exhibited reversible photochromism under UV and solar irradiation, developing fast responses and intense coloration. The fabrics coated with SiO2@S1 and SiO2@S2 showed rapid color changes and high contrasts (ΔE*ab = 39-52), despite presenting slower bleaching kinetics (2-3 h to fade to the original color), whereas the textiles coated with SiO2@S3 and SiO2@S4 exhibited excellent engagement between coloration and decoloration rates (coloration and fading times of 1 and 2 min, respectively; ΔE*ab = 27-53). The PU-based fabrics showed excellent results during the washing fastness tests, whereas the AC-based textiles evidenced good results only when a protective transfer film was applied over the printed design.

Robust Mesoporous CoMo/γ-Al2O3 Catalysts from Cyclodextrin-Based Supramolecular Assemblies for Hydrothermal Processing of Microalgae: Effect of the Preparation Method

Hydrothermal liquefaction (HTL) is a promising technology for the production of biocrude oil from microalgae. Although this catalyst-free technology is efficient under high-temperature and high-pressure conditions, the biocrude yield and quality can be further improved by using heterogeneous catalysts. The design of robust catalysts that preserve their performance under hydrothermal conditions will be therefore very important in the development of biorefinery technologies. In this work, we describe two different synthetic routes (i.e., impregnation and cyclodextrin-assisted one-pot colloidal approach), for the preparation in aqueous phase of six high surface area CoMo/γ-Al2O3 catalysts. Catalytic tests performed on the HTL of Nannochloropsis gaditana microalga indicate that solids prepared by the one-pot colloidal approach show higher hydrothermal stability and enhanced biocrude yield with respect to the catalyst-free test. The positive effect of the substitution of the block copolymer Tetronic T90R4 for Pluronic F127 in the preparation procedure was evidenced by diffuse reflectance UV-visible spectroscopy, X-ray diffraction, N2-adsorption-desorption, and H2-temperature-programmed reduction measurements and confirmed by the higher quality of the obtained biocrude, which exhibited lower oxygen content and higher-energy recovery equal to 62.5% of the initial biomass.