Biomimetic approach for an articular cartilage patch: Combination of decellularized cartilage matrix and silk-elastin-like-protein (SELP) hydrogel

Articular cartilage degradation due to injury, disease and aging is a common clinical issue as current regenerative therapies are unable to fully replicate the complex microenvironment of the native tissue which, being avascular, is featured by very low ability to self-regenerate. The extracellular matrix (ECM), constituting almost 90% of the entire tissue, plays a critical role in its function and resistance to compressive forces. In this context, the current tissue engineering strategies are only partially effective in restoring the biology and function of the native tissue. A main issue in tissue regeneration is treatment failure due to scarce integration of the engineered construct, often following a gradual detachment of the graft. In this scenario, we aimed to create an adhesive patch able to adequately support cartilage regeneration as a promising tool for the treatment of cartilage injuries and diseases. For this, we produced an engineered construct composed of decellularized ECM (dECM) obtained from horse joint cartilage, to support tissue regeneration, coupled with a Silk-Elastin-Like Proteins (SELP) hydrogel, which acts as a biological glue, to guarantee an adequate adherence to the host tissue. Following the production of the two biomaterials we characterized them by assessing: 1) dECM morphological, chemical, and ultrastructural features along with its capability to support chondrocyte proliferation, specific marker expression and ECM synthesis; 2) SELP microarchitecture, cytocompatibility and mechanical properties. Our results demonstrated that both materials hold unique properties suitable to be exploited to produce a tailored microenvironment to support cell growth and differentiation providing a proof of concept concerning the in vitro biological and mechanical efficacy of the construct. The SELP hydrogel displayed a very interesting physical behavior due to its high degree of resistance to mechanical stress, which is generally associated with physiological mechanical load during locomotion. Intriguingly, the shear-thinning behavior of the hydrogel may also make it suitable to be applied and spread over non-homogeneous surfaces, therefore, we hypothesize that the hybrid biomaterial proposed may be a real asset in the treatment of cartilage defects and injuries.

pH-Responsive Hybrid Nanoassemblies for Cancer Treatment: Formulation Development, Optimization, and In Vitro Therapeutic Performance

Current needs for increased drug delivery carrier efficacy and specificity in cancer necessitate the adoption of intelligent materials that respond to environmental stimuli. Therefore, we developed and optimized pH-triggered drug delivery nanoassemblies that exhibit an increased release of doxorubicin (DOX) in acidic conditions typical of cancer tissues and endosomal vesicles (pH 5.5) while exhibiting significantly lower release under normal physiological conditions (pH 7.5), indicating the potential to reduce cytotoxicity in healthy cells. The hybrid (polymeric/lipid) composition of the lyotropic non-lamellar liquid crystalline (LNLCs) nanoassemblies demonstrated high encapsulation efficiency of the drug (>90%) and high drug loading content (>7%) with colloidal stability lasting at least 4 weeks. Confocal microscopy revealed cancer cellular uptake and DOX-loaded LNLCs accumulation near the nucleus of human hepatocellular carcinoma cells, with a large number of cells appearing to be in apoptosis. DOX-loaded LNLCs have also shown higher citotoxicity in cancer cell lines (MDA-MB 231 and HepG2 cell lines after 24 h and in NCI-H1299 cell line after 48 h) when compared to free drug. After 24 h, free DOX was found to have higher cytotoxicity than DOX-loaded LNLCs and empty LNLCs in the normal cell line. Overall, the results demonstrate that DOX-loaded LNLCs have the potential to be explored in cancer therapy.

Uncovering the Promiscuous Activity of IL-6 Proteins: A Multi-Dimensional Analysis of Phylogeny, Classification and Residue Conservation

The IL-6 family of cytokines, known for their pleiotropic behavior, share binding to the gp130 receptor for signal transduction with the necessity to bind other receptors. Leukemia inhibitory factor receptor is triggered by the IL-6 family proteins: leukemia inhibitory factor (LIF), oncostatin-m (OSM), cardiotrophin-1 (CT-1), ciliary neurotrophic factor (CNTF) and cardiotrophin-like cytokine factor 1 (CLCF1). Besides the conserved binding sites to the receptor, not much is known in terms of diversity and characteristics of these proteins in different organisms. Herein, we describe the sequence analysis of LIF, OSM and CT-1 from several organisms, and m17, a LIF ortholog found in fishes, regarding its phylogenetics, intrinsic properties and the impact of conserved residues on structural features. Sequences were identified in 7 classes of vertebrates, showing high conservation values in binding site III, but protein-dependent results on binding site II. GRAVY, isoelectric point and molecular weight parameters were relevant to differentiate classes in each protein and to enable, for the first time and with high fidelity, the prediction of both organism class and protein type just using machine learning approaches. OSM sequences from primates showed an increased BC loop when compared to the remaining mammals, which could influence binding to OSM receptor and tune signaling pathways. Overall, this study highlights the potential of sequence diversity analysis to understand IL-6 cytokine family evolution, showing conservation of function-related motifs and evolution of class and protein-dependent characteristics. Our results could impact future medical treatment of disorders associated with imbalances in these cytokines. This article is protected by copyright. All rights reserved.

Elastin-like Polypeptides in Development of Nanomaterials for Application in the Medical Field

Elastin-like polypeptides (ELPs) are biopolymers formed by amino acid sequences derived from tropoelastin. These biomolecules can be soluble below critical temperatures, forming aggregates at higher temperatures, which makes them an interesting source for the design of different nanobiomaterials. These nanobiomaterials can be obtained from heterologous expression in several organisms such as bacteria, fungi, and plants. Thanks to the many advantages of ELPs, they have been used in the biomedical field to develop nanoparticles, nanofibers, and nanocomposites. These nanostructures can be used in multiple applications such as drug delivery systems, treatments of type 2 diabetes, cardiovascular diseases, tissue repair, and cancer therapy. Thus, this review aims to shed some light on the main advances in elastin-like-based nanomaterials, their possible expression forms, and importance to the medical field.

Biocomposites of Silk-Elastin and Essential Oil from Mentha piperita Display Antibacterial Activity

In this study, novel antimicrobial biocomposite films comprising a genetically engineered silk-elastin protein polymer (SELP) and essential oil from Mentha piperita (MP_EO) have been fabricated and tested for the antibacterial performance. SELP/MP_EO biocomposite films were prepared by solvent casting using water as the solvent and aqueous emulsions of MP_EO at different concentrations. Emulsions of MP_EO were investigated, showing that the mixing method, relative amount of surfactant, and the presence of SELP influence particle size and homogeneity. The aqueous emulsions of SELP/MP_EO were characterized by a population of particles between 100 and 300 nm, depending on the MP_EO concentration. The emulsified oil droplets at the highest concentration showed to be homogeneously distributed into the SELP matrix and demonstrated antibacterial activity against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. Moreover, the antibacterial activity of the biocomposite films was retained after a period of storage for 7 days at 4 °C. The formulation of composites comprising natural active fillers and recombinant protein polymers opens opportunities to develop new green, functional biocomposite materials, paving the way for a new generation of multifunctional materials.

Postoperative pain after endodontic treatment of necrotic teeth submitted to large apical preparation using oscillatory kinematics

Background

Regardless of the technique applied for chemomechanical preparation, postoperative pain is a very relevant matter in endodontics. Objective: To evaluate postoperative pain after endodontic treatment of necrotic teeth submitted to large apical preparation (LAP) using oscillatory kinematics.

Material and Methods

The sample included 60 asymptomatic necrotic teeth with or without apical radiolucency, and with normal periodontal status, referred for endodontic treatment. Following initial procedures, the position and approximate size of the apical constriction were determined by using an apex locator and K Flexofiles, respectively. The chemomechanical preparation was conducted using oscillatory kinematics and 2.5ml of 2.5% NaOCl at each file change to achieve LAP, and the filling was done with Tagger’s hybrid technique and EndoFill sealer. Phone calls were made to all the patients at 24, 48 and 72 hours after treatment to request their classification of postoperative pain, and data were submitted to statistical analysis.

Results

Only 3 patients (5%) reported severe pain after 72 hours. Moderate pain was reported by 17, 9 and 1 patient after 24, 48 and 72 hours, respectively (P = 0.000). However, paired analyses showed a statistically significant difference only between 24 and 72 hours (P = 0.001), and 48 and 72 hours (P = 0.014). Age and tooth type did not influence the postoperative pain, regardless of time (P> 0.05). After 72 hours, women experienced significantly more pain than men (P = 0.012), and teeth without periradicular lesion were more sensitive that teeth with perirradicular lesion (P = 0.027).

Conclusions

Acute or moderate postoperative pain was uncommon after endodontic treatment of necrotic teeth submitted to LAP using oscillatory kinematics.

Key words:Endodontic treatment, oscillatory kinematics, postoperative pain, pulp necrosis.

Mesalazine and inflammatory bowel disease - From well-established therapies to progress beyond the state of the art

Inflammatory bowel disease incidence has been constantly rising for the past few decades. Current therapies attempt to mitigate its symptoms since no cure is established. The most commonly prescribed drug for these patients is 5-aminosalicylic acid (5-ASA). Due to the low rate and seriousness of side effects compared to other therapies, 5-ASA is still largely prescribed in many stages of inflammatory bowel disease, including scenarios where evidence suggests low effectiveness. Although commercialized formulations have come a long way in improving pharmacokinetics, it is still necessary to design and develop novel delivery systems capable of increasing effectiveness at different stages of the disease. In particular, micro- and nano-sized particles might be the key to its success in Crohn's disease and in more serious disease stages. This review provides an overview on the clinical significance of 5-ASA formulations, its limitations, challenges, and the most recent micro- and nanoparticle delivery systems being designed for its controlled release. Emergent alternatives for 5-ASA are also discussed, as well as the future prospects for its application in inflammatory bowel disease therapies.

Novel concept of exosome-like liposomes for the treatment of Alzheimer's disease

Exosomes are cell-derived vesicles that act as carriers for proteins and nucleic acids, with therapeutic potential and high biocompatibility. We propose a new concept of exosome-like liposomes for controlled delivery. The goal of this work was to develop a new type of liposomes with a unique mixture of phospholipids, similar to naturally occurring exosomes but overcoming their limitations of heterogeneity and low productivity, for therapeutic delivery of bioactive compounds. Curcumin was chosen as model compound, as it is a phytochemical molecule known to have antioxidant and anti-inflammatory properties, which can protect the brain against oxidative stress and reduce β-amyloid accumulation, major hallmarks of Alzheimer's disease (AD). These new liposomes can efficiently encapsulate hydrophobic curcumin, yielding particles with a size smaller than 200 nm, and a polydispersity index lower than 0.20, which make them ideal for crossing the blood-brain barrier. These particles have a long shelf life, being stable up to 6 months. The curcumin encapsulation efficiency was higher than 85% (up to approximately 94%). Curcumin-loaded liposomes were not cytotoxic (up to 20 μM curcumin, and 200 μM of exo-liposomes), and significantly reduced oxidative stress induced in SH-SY5Y neuronal cells, indicating their potential for neuroprotection. They also do not show any toxicity and are internalized in zebrafish embryos, concentrating in lipid enriched areas, as the brain and the yolk sac. Such innovative carriers are a new effective approach to deliver drugs into the brain, as these are stable, protect the cargo and are uptaken by neuronal cells. Upon internalization, liposomes release the therapeutic biomolecules, resulting in successful neuroprotection, being a positive alternative strategy for AD therapy.

Sequencing batch airlift reactors (SBAR): a suitable technology for treatment and valorization of mineral oil wastewaters towards lipids production

Produced water (PW) and spent oil-based wastewaters are some of the largest mineral oil wastewaters produced. Due to the high toxicity of hydrocarbons, several countries set stringent discharge limits and its treatment is compulsory before discharge. In this work, biological treatment of mineral oil wastewaters coupled with the production of bacterial lipids is demonstrated in sequential batch airlift reactors (SBAR). Two SBAR (2 L working volume) were used for treatment of PW and lubricant-based wastewater (LW), inoculated with Alcanivorax borkumensis SK2 (SBAR_Ab+PW) and Rhodococcus opacus B4 (SBAR_R.o+LW), respectively. A total petroleum hydrocarbon removal (TPH) efficiency up to 96% and 80% were achieved for SBAR_Ab+PW and SBAR_R.o+LW, respectively. Intracellular lipids production in SBAR_Ab+PW increased when lower TPH/N ratios and higher feast stage duration were applied (up to 0.74 g g^-1 cell dry weight (CDW)), whereas in SBAR_R.o+LW higher lipids production was observed for higher TPH/N ratios (0.94 g g^-1 in CDW). Triacylglycerols (TAG) were the main intracellular lipid accumulated in both SBAR_Ab+PW and SBAR_R.o+LW operations, while wax ester (WE) production was only observed extracellularly in the SBAR_Ab+PW.

Protein-Based Films Functionalized with a Truncated Antimicrobial Peptide Sequence Display Broad Antimicrobial Activity

The increasing bacterial resistance to antibiotics is driving strong demand for new antimicrobial biomaterials. This work describes the fabrication of free-standing films exhibiting antimicrobial properties by combining, in the same polypeptide chain, an elastin-like recombinamer comprising 200 repetitions of the pentamer VPAVG (A200) and an 18-amino-acid truncated variant of the antimicrobial peptide BMAP-28, termed BMAP-18. The fusion protein BMAP-18A200 was overexpressed and conveniently purified by a simplified and scalable nonchromatographic process. Free-standing films of BMAP-18A200 demonstrated to be stable without requiring cross-linking agents and displayed high antimicrobial activity against skin pathogens including Gram-negative and Gram-positive bacteria as well as unicellular and filamentous fungi. The antimicrobial activity of the films was mediated by direct contact of cells with the film surface, resulting in compromised structural integrity of microbial cells. Furthermore, the BMAP-18A200 films showed no cytotoxicity on normal human cell lines (skin fibroblasts and keratinocytes). All of these results highlight the potential of these biotechnological multifunctional polymers as new drug-free materials to prevent and treat microbial infections.

Design of polymeric core-shell carriers for combination therapies

Particle engineering for co-delivery of drugs has the potential to combine multiple drugs with different pharmaceutical mechanisms within the same carrier, increasing the therapeutic efficiency while improving patient compliance. This work proposes a novel approach for producing polymer-polymer core-shell microparticles by multi-step processing of emulsion and spray drying. The particle core was obtained by an oil-in-water emulsion of poly(ε-caprolactone) (PCL) loaded with curcumin (CM), followed by the resuspension in poly(vinyl alcohol) (PVA) containing ciprofloxacin (CPx) forming the shell layer by spray-drying. The obtained core-shell particles showed an average size of 3.8 ± 1.2 μm, which is a suitable size for inhalation therapies. The spatial distribution of the drugs was studied using synchrotron-based macro attenuated total reflection Fourier transform infrared (macro ATR-FTIR) microspectroscopy to map the chemical distribution of the components within the particles and supported the presence of CM and CPx in the core and shell layers, respectively. The formation of the core-shell structure was further supported by the differences in the release profile of CM from these particles, when compared to the release profile observed for the single particle structure (PCL-CM). Both empty and drug-loaded carriers (up to 100 μg.mL^-1) showed no cytotoxic effects on A549 cells while exhibiting the antibacterial activity of CPx against Gram-positive and Gram-negative bacteria. These polymer core-shell microparticles provide a promising route for the combination and sequential drug release therapies, with the potential to be used in inhalation therapies.

Does wild rabbit population size affect connectivity?

<p>Wild rabbit is a relevant species in the Iberian Peninsula due to its ecological  and economic roles. Conservationists and game managers therefore have a shared interest in assuring the existence of resilient and sustainable populations. Although management principles and guidelines are  mostly known and understood, often the results are not as good as expected. Local abundance can vary significantly even in short periods, while the colonisation of adjacent territories is uncommon, probably due to the territorial behaviour of the species. Aware that the foundation of nuclei requires interaction among individuals, we hypothesised that rabbit abundance plays a significant part in population connectivity. In order to find out whether the population size affects nuclei connectivity, we conducted a graph theory-based connectivity analysis. The results confirm that connectivity grows with rabbit abundance, but only to a certain degree, and there is a spatial separation of the nuclei regardless of the population size. These outcomes suggest that a comprehensive wild rabbit population increment plan should address both the abundance and spatial distribution, but should not aim at achieving a continuous distribution of wild rabbit with constant or similar abundance. Regarding specific management actions, we argue that in restocking operations new nuclei should be located within dispersal range from the existing ones to promote inter-nuclei connectivity, but not too close, as the nuclei segregation tendency is likely to persist due to the species’ territoriality.</p>

Polymeric Electrospun Fibrous Dressings for Topical Co-delivery of Acyclovir and Omega-3 Fatty Acids

Herpetic infections caused by Herpes simplex virus (HSV) are among the most common human infections, affecting more than two quarters of the world's population. The standard treatment for orofacial herpes is the administration of antiviral drugs, mainly acyclovir (ACV). However, current products are mostly based on semisolid formulations that have limited ability to promote drug skin penetration and tend to leak from the application site, thus showing reduced ability to sustain local drug residence. This work reports on the production of poly (ε-caprolactone) (PCL) fibrous matrices with ACV and omega-3 fatty acids (ω3) for application as dressings to the topical treatment of orofacial herpes. PCL fibrous matrices with the co-incorporated bioactive compounds were obtained by electrospinning and characterized regarding their morphology, chemical, physical, and mechanical properties. The potential use of the developed polymeric fibrous matrices for topical applications was evaluated by: (i) the release kinetics of the bioactive compounds; (ii) the occlusive factor of the fibrous mat; (iii) ACV skin permeation capacity; and (iv) the cytotoxicity in a keratinocyte cell line. PCL fibrous matrices loaded with the bioactive compounds presented a smooth morphology and a good balance between flexibility and hardness essential to be durable for handling, while having a desirable texture to be used comfortably. The fibrous mat also provided a sustained release of ACV during 96 h and improved the skin permeability of this drug (Kp = 0.00928 ± 0.000867 cm/h) presenting also high porosity (74%) and a water vapor transmission rate (WVTR) of 881 ± 91 g/m²day, essential to maintain moist and oxygen for faster healing of herpes lesions. Furthermore, cytotoxicity studies suggest that the fibrous mat are safe for topical application. Overall, the PCL based electrospun fibrous matrices with ACV and ω3 hereby described have the potential to be used as therapeutic bandage systems for the treatment of orofacial herpes.

Rational Development of Liposomal Hydrogels: A Strategy for Topical Vaginal Antiretroviral Drug Delivery in the Context of HIV Prevention

HIV/AIDS stands as a global burden, and vaginal microbicides constitute a promising strategy for topical pre-exposure prophylaxis. Preceding the development of a microbicide containing tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC), in silico and in vitro studies were performed to evaluate the physicochemical characteristics of both drugs, and to study their biophysical impact in lipid model systems. Results from these pre-formulation studies defined hydrogels as adequate vehicles to incorporate TDF-loaded liposomes and FTC. After studying interactions with mucin, zwitterionic liposomes with a mean diameter of 134 ± 13 nm, an encapsulation TDF efficiency of approximately 84%, and a transition temperature of 41 °C were selected. The chosen liposomal formulation was non-cytotoxic to HEC-1-A and CaSki cells, and was able to favor TDF permeation across polysulfone membranes (J_ss = 9.9 μg·cm^-2·h^-1). After the incorporation of TDF-loaded liposomes and FTC in carbomer hydrogels, the drug release profile was sustained over time, reaching around 60% for both drugs within 3-6 h, and best fitting the Weibull model. Moreover, liposomal hydrogels featured pseudoplastic profiles that were deemed suitable for topical application. Overall, the proposed liposomal hydrogels may constitute a promising formulation for the vaginal co-delivery of TDF/FTC.

Production of bioactive hepcidin by recombinant DNA tagging with an elastin-like recombinamer

With the lack of new chemical antibiotics and increasing pathogen resistance to those available, new alternatives are being explored. Antimicrobial peptides (AMPs) with a broad range of effects, including antibacterial, antifungal, and antiviral actions, have emerged as one of the options. They can be produced by recombinant DNA technology, but the chromatographic methods used for peptide purification are expensive and time consuming. Here, we describe the design, production, purification and assessment of the antibacterial activity of the human peptide hepcidin, using an elastin-like recombinamer as fusion partner. The recombinant protein Hep-A200 was produced in Escherichia coli and purified by a non-chromatographic procedure, exploiting the thermal properties of the A200 elastin-like recombinamer. Recombinant Hep-A200 was found to retain antibacterial activity against Gram-positive and Gram-negative species.

Antibacterial and Antifungal Activity of Poly(Lactic Acid)-Bovine Lactoferrin Nanofiber Membranes

Antimicrobial materials have become relevant for local therapies preventing microbial resistance induced by systemic antibiotic treatments. This work reports the development of electrospun poly(lactic acid) (PLLA) nanofiber membranes loaded with bovine lactoferrin (bLF) up to 20 wt%. The membranes present smooth and nondefective fibers with mean diameters between 717 ± 197 and 495 ± 127 nm, and an overall porosity of ≈80%. The hydrophobicity of the PLLA membranes is reduced by the presence of bLF. The release profile of bLF correlates with an anomalous transport model, with 17.7 ± 3.6% being released over 7 weeks. The nanofiber mats show no cytotoxicity on human skin fibroblasts and even promote cell proliferation after short exposure periods. Furthermore, the developed membranes display antifungal activity against Aspergillus nidulans by inhibiting spore germination and mycelial growth. These results evidence the strong potential of bLF-PLLA nanofiber membranes to be used as antifungal dressings.

Silk-based biomaterials functionalized with fibronectin type II promotes cell adhesion

The objective of this work was to exploit the fibronectin type II (FNII) module from human matrix metalloproteinase-2 as a functional domain for the development of silk-based biopolymer blends that display enhanced cell adhesion properties. The DNA sequence of spider dragline silk protein (6mer) was genetically fused with the FNII coding sequence and expressed in Escherichia coli. The chimeric protein 6mer+FNII was purified by non-chromatographic methods. Films prepared from 6mer+FNII by solvent casting promoted only limited cell adhesion of human skin fibroblasts. However, the performance of the material in terms of cell adhesion was significantly improved when 6mer+FNII was combined with a silk-elastin-like protein in a concentration-dependent behavior. With this work we describe a novel class of biopolymer that promote cell adhesion and potentially useful as biomaterials for tissue engineering and regenerative medicine.

STATEMENT OF SIGNIFICANCE

This work reports the development of biocompatible silk-based composites with enhanced cell adhesion properties suitable for biomedical applications in regenerative medicine. The biocomposites were produced by combining a genetically engineered silk-elastin-like protein with a genetically engineered spider-silk-based polypeptide carrying the three domains of the fibronectin type II module from human metalloproteinase-2. These composites were processed into free-standing films by solvent casting and characterized for their biological behavior. To our knowledge this is the first report of the exploitation of all three FNII domains as a functional domain for the development of bioinspired materials with improved biological performance. The present study highlights the potential of using genetically engineered protein-based composites as a platform for the development of new bioinspired biomaterials.

Analysis of an astounding aggregation of Ranzania laevis (Molidae: Actinopterygii) in the tropical south-western Atlantic

Unusual catches of more than 4200 kg of the slender sunfish Ranzania laevis are described from the south-western Atlantic, corresponding to the largest aggregation records for the species. These unexpected records were associated with unusually warm currents in the area. Males and females were physiologically able to spawn at the moment of capture, suggesting the occurrence of reproductive aggregation in this species.

Wildfire patterns and landscape changes in Mediterranean oak woodlands

Fire is infrequent in the oak woodlands of southern Portugal (montado) but large and severe fires affected these agro-forestry systems in 2003-2005. We hypothesised transition from forest to shrubland as a fire-driven process and investigated the links between fire incidence and montado change to other land cover types, particularly those related with the presence of pioneer communities (generically designed in this context as "transitions to early-successional communities"). We present a landscape-scale framework for assessing the probability of transition from montado to pioneer communities, considering three sets of explanatory variables: montado patterns in 1990 and prior changes from montado to early-successional communities (occurred between 1960 and 1990), fire patterns, and spatial factors. These three sets of factors captured 78.2% of the observed variability in the transitions from montado to pioneer vegetation. The contributions of fire patterns and spatial factors were high, respectively 60.6% and 43.4%, the influence of montado patterns and former changes in montado being lower (34.4%). The highest amount of explained variation in the occurrence of transitions from montado to early-successional communities was related to the pure effect of fire patterns (19.9%). Low spatial connectedness in montado landscape can increase vulnerability to changes, namely to pioneer vegetation, but the observed changes were mostly explained by fire characteristics and spatial factors. Among all metrics used to characterize fire patterns and extent, effective mesh size provided the best modelling results. Transitions from montado to pioneer communities are more likely in the presence of high values of the effective mesh size of total burned area. This cross-boundary metric is an indicator of the influence of large fires in the distribution of the identified transitions and, therefore, we conclude that the occurrence of large fires in montado increases its probability of transition to shrubland.

Antibacterial performance of bovine lactoferrin-fish gelatine electrospun membranes

The increase of antibiotic resistant microorganisms urged the development and synthesis of novel antimicrobial biomaterials to be employed in a broad range of applications, ranging from food packaging to medical devices. This work describes the production and characterization of a protein-based electrospun fibrous membranes bearing antimicrobial properties. Its composition is exclusively comprised of proteins, with fish gelatine as structural matrix and bovine lactoferrin (bLF) as the active antimicrobial agent. The bLF bactericidal effect was determined against clinical isolates of Escherichia coli and Staphylococcus aureus through microdilution assays. Two distinctive methods were used to incorporate bLF into the fish gelatine nanofibres: (i) as a filler in the electrospinning formulation with concentrations of 2, 5 and 10 (wt%), and cross-linked with glutaraldehyde vapour, in order to achieve stability in aqueous solution; and (ii) through adsorption in a solution with 40mgmL(-1) bLF. Fourier transform infrared spectroscopy analysis showed that the structure of both proteins remained intact through the electrospinning blending and cross-linking procedure. Remarkable antibacterial properties were obtained with membranes containing 5% and 10% bLF with a bacterial reduction of approximately 90% and 100%, respectively.

48 GLOBAL GENE EXPRESSION PATTERN OF BOS INDICUS AND BOS TAURUS VITRIFIED EMBRYOS

The cryopreservation of in vitro-produced (IVP) bovine embryos is one of the most challenging areas of the assisted reproductive biotechnologies. The aim of the present study was to evaluate the global gene expression pattern of Bos indicus (Nellore) and Bos taurus (Simmental) IVP embryos after vitrification. Follicular aspiration was performed on Nellore (n = 14) and Simmental (n = 14) cows, and oocytes (n = 840 and 450; respectively) were submitted to in vitro maturation and in vitro fertilization. Presumptive zygotes were denuded and cultured in SOFaa with 0.5% BSA and 2.5% FCS during 7 days under standard culture conditions. Blastocysts (grade 1 and 2) were vitrified, warmed, and cultured for an additional 12 h under the same conditions. Nellore (n = 8) and Simmental (n = 8) IVP blastocysts considered viable after vitrification, with re-expanded blastocoel, were submitted to total RNA extraction (PicoPure, Arcturus, Applied Biosystems®, Foster Dity, CA, USA), DNAse I treatment (Qiagen®, Valencia, CA, USA), and amplification (RiboAmp, Applied Biosystems®). Fragmented cRNA were obtained through 3′IVT Express Kit (Affymetrix®, Santa Clara, CA, USA) to perform the hybridization using GeneChip Bovine Genome Array (Affymetrix®). Microarray data analysis was performed using the FlexArray 1.6.1.1 software. Genes with at least a 1.5-fold change and a P-value of less than 0.05 were considered differentially expressed. Of the 1278 genes differentially expressed between Bos taurus and Bos indicus vitrified embryos, 1108 were annotated, with 1193 genes up-regulated and 85 genes down-regulated in Bos taurus compared with Bos indicus IVP vitrified embryos. Differentially expressed genes were associated with the functional networks of cell cycle, cellular movement and DNA replication, recombination and repair; RNA post-transcriptional modifications; gene expression, protein synthesis; RNA damage and repair; cellular function and maintenance; and cell death and survival. The top 6 canonical pathways generated by Ingenuity Pathway Analysis® with the differentially expressed genes were ELF2 signalling, oxidative phosphorylation, tricarboxylic acid cycle, protein ubiquitination pathway, mTOR signalling, and IGF-1 signalling. In conclusion, Bos taurus IVP embryos seem to trigger different cellular response mechanisms to the vitrification stress in comparison with Bos indicus IVP embryos. Differential response is mainly represented by different expression profiles of genes regulating important canonical pathways involved in cellular response to stress that could be related with the higher post-cryopreservation survival capacity observed in Bos taurus embryos.Research was supported by FAPESP, CNPq, FAPERGS, and LNBio – National Laboratory of Biosciences/MCT.

82 EFFECT OF HIGH FETAL CALF SERUM CONCENTRATION IN THE GENE EXPRESSION PATTERN OF IN VITRO PRODUCED BOVINE EMBRYOS

Even though FCS provides energy substrates, amino acids, vitamins, growth factors, and heavy-metal chelators, its supplementation has been associated with several embryo abnormalities such as mitochondrial degeneration, metabolic deviations, excessive lipid accumulation, and decreased embryo survival after cryopreservation. The aim of the present study was to evaluate the effect of high FCS concentration in the gene expression pattern of in vitro-produced bovine embryos. Slaughterhouse ovaries were used to obtain oocytes (N = 360), which were matured and fertilized in vitro (Day 0). Presumptive zygotes were divided in 2 culture media: with low (SOFaa with 0.5% BSA and 2.5% FCS) or high (SOFaa with 0.5% BSA and 10% FCS) FCS concentration. Cleavage was evaluated on Day 3. Embryo development was evaluated after 7 days under standard culture conditions (at 38.5°C in atmosphere of 5% O2, 5% CO2, and 90% N2). The produced blastocysts were placed in PBS solution and washed five times. A single blastocyst was frozen in a minimal volume of PBS and stored at –80°C until RNA extraction. Total RNA extraction was performed using the PicoPure RNA isolation Kit (Applied Biosystems®, Foster City, CA, USA). Extracted RNA was evaluated through 2100-Bioanalyzer (Agilent Technologies®, Palo Alto, CA, USA) and DNAse treated (Qiagen®, Valencia, CA, USA). RiboAmp RNA Amplification Kit (Applied Biosystems®) was used to amplify the RNA (T7 RNA polymerase-catalysed amplification reaction). The aRNA output was evaluated through NanoDrop ND-1000 (NanoDrop Technologies®, Wilmington, DE, USA). A biotin-labelled cRNA and fragmented cRNA were obtained through 3′IVT Express Kit (Affymetrix®, Santa Clara, CA, USA) to perform the hybridization (N = 3 per group) using GeneChip Bovine Genome Array (Affymetrix®). Following hybridization, probe arrays were washed, stained, and scanned. Microarray data analysis was performed in the software FlexArray 1.6.1.1. Genes with a fold change of at least 1.5 and a probability of P < 0.05 were considered differentially expressed. The data from in vitro embryo production were analysed through the PROC GLM (SAS Institute Inc., Cary, NC, USA). Cleavage rate (81.4 ± 1.5 and 85.5 ± 1.4) and blastocyst production (41.8 ± 2.4 and 47.2 ± 2.8) were not different (P > 0.05) between low and high FCS concentrations, respectively. A total of 40 genes were differentially expressed between low and high FCS concentration. A total of 28 genes were annotated, with 37 genes up-regulated and 3 genes down-regulated by high FCS concentration. The associated network functions of gene expression, RNA damage and repair, and post-transcriptional modification; and cell-to-cell signalling and interaction were generated by Ingenuity Pathway Analysis® (Redwood City, CA, USA). Differentially expressed genes involved in carbohydrate metabolism (GAPVD1, MGAT4A), lipid metabolism (ELOVL5), cellular assembly and organisation (EZR, LRP2), and cell death and survival (DRT8) were identified. In conclusion, high FCS supplementation was associated with different expression profiles of genes regulating carbohydrate and lipid metabolism, cellular assembly and organisation, and cell death and survival. The authors acknowledge support from FAPESP and LNBio-CNPEM.

Anomalous colour in Neotropical mammals: a review with new records for Didelphis sp. (Didelphidae, Didelphimorphia) and Arctocephalus australis (Otariidae, Carnivora)

Anomalous colourations occur in many tropical vertebrates. However, they are considered rare in wild populations, with very few records for the majority of animal taxa. We report two new cases of anomalous colouration in mammals. Additionally, we compiled all published cases about anomalous pigmentation registered in Neotropical mammals, throughout a comprehensive review of peer reviewed articles between 1950 and 2010. Every record was classified as albinism, leucism, piebaldism or eventually as undetermined pigmentation. As results, we report the new record of a leucistic specimen of opossum (Didelphis sp.) in southern Brazil, as well as a specimen of South American fur seal (Arctocephalus australis) with piebaldism in Uruguay. We also found 31 scientific articles resulting in 23 records of albinism, 12 of leucism, 71 of piebaldism and 92 records classified as undetermined pigmentation. Anomalous colouration is apparently rare in small terrestrial mammals, but it is much more common in cetaceans and michrochiropterans. Out of these 198 records, 149 occurred in cetaceans and 30 in bats. The results related to cetaceans suggest that males and females with anomolous pigmentation are reproductively successful and as a consequence their frequencies are becoming higher in natural populations. In bats, this result can be related to the fact these animals orient themselves primarily through echolocation, and their refuges provide protection against light and predation. It is possible that anomalous colouration occurs more frequently in other Neotropical mammal orders, which were not formally reported. Therefore, we encourage researchers to publish these events in order to better understand this phenomenon that has a significant influence on animal survival.

Batch production of a silk-elastin-like protein in E. coli BL21(DE3): key parameters for optimisation

Background

Silk-elastin-like proteins (SELPs) combining the physicochemical and biological properties of silk and elastin have a high potential for use in the pharmaceutical, regenerative medicine and materials fields. Their development for use is however restrained by their production levels. Here we describe the batch production optimisation for a novel recently described SELP in the pET-E. coli BL21(DE3) expression system. Both a comprehensive empirical approach examining all process variables (media, induction time and period, temperature, pH, aeration and agitation) and a detailed characterisation of the bioprocess were carried out in an attempt to maximise production with this system.

Results

This study shows that maximum SELP volumetric production is achieved at 37°C using terrific broth at pH 6–7.5, a shake flask volume to medium volume ratio of 10:1 and an agitation speed of 200 rpm. Maximum induction is attained at the beginning of the stationary phase with 0.5 mM IPTG and an induction period of at least 4 hours. We show that the selection agents ampicillin and carbenicillin are rapidly degraded early in the cultivation and that plasmid stability decreases dramatically on induction. Furthermore, acetate accumulates during the bioprocess to levels which are shown to be inhibitory to the host cells. Using our optimised conditions, 500 mg/L of purified SELP was obtained.

Conclusions

We have identified the optimal conditions for the shake flask production of a novel SELP with the final production levels obtained being the highest reported to date. While this study is focused on SELPs, we believe that it could also be of general interest to any study where the pET (ampicillin selective marker)-E. coli BL21(DE3) expression system is used. In particular, we show that induction time is critical in this system with, in contrast to that which is generally believed, optimal production being obtained by induction at the beginning of the stationary phase. Furthermore, we believe that we are at or near the maximum productivity for the system used, with rapid degradation of the selective agent by plasmid encoded β-lactamase, plasmid instability on induction and high acetate production levels being the principal limiting factors for further improved production.

High level expression and facile purification of recombinant silk-elastin-like polymers in auto induction shake flask cultures

Silk-elastin-like polymers (SELPs) are protein-based polymers composed of repetitive amino acid sequence motifs found in silk fibroin (GAGAGS) and mammalian elastin (VPGVG). These polymers are of much interest, both from a fundamental and applied point of view, finding potential application in biomedicine, nanotechnology and as materials. The successful employment of such polymers in such diverse fields, however, requires the ready availability of a variety of different forms with novel enhanced properties and which can be simply prepared in large quantities on an industrial scale. In an attempt to create new polymer designs with improved properties and applicability, we have developed four novel SELPs wherein the elastomer forming sequence poly(VPGVG) is replaced with a plastic-like forming sequence, poly(VPAVG), and combined in varying proportions with the silk motif. Furthermore, we optimised a simplified production procedure for these, making use of an autoinduction medium to reduce process intervention and with the production level obtained being 6-fold higher than previously reported for other SELPs, with volumetric productivities above 150 mg/L. Finally, we took advantage of the known enhanced stability of these polymers in developing an abridged, non-chromatographic downstream processing and purification protocol. A simple acid treatment allowed for cell disruption and the obtention of relative pure SELP in one-step, with ammonium sulphate precipitation being subsequently used to enable improved purity. These simplified production and purification procedures improve process efficiency and reduce costs in the preparation of these novel polymers and enhances their potential for application.

80 GLOBAL GENE EXPRESSION PATTERNS OF FRESH AND VITRIFIED IN VITRO-PRODUCED BOVINE BLASTOCYSTS

Over the past decades, there have been great advances in in vitro production (IVP) systems with improved culture methods and new knowledge regarding embryo genetics, physiology, ultrastructure, and morphology. Nevertheless, a major obstacle for dissemination of this technology is the great sensitivity of IVP embryos to cryopreservation. The objective was to study the global gene-expression patterns of fresh and vitrified IVP bovine embryos. Oocytes (N = 1290) were matured and fertilized in vitro (Day 0). Presumptive zygotes were cultured in SOFaa with 0.5% BSA and 2.5% of FCS. Cleavage and blastocyst production was evaluated after 3 and 7 days under standard culture conditions (at 38.5°C in atmosphere of 5% O2, 5% CO2, and 90% N2). On Day 7, half of the blastocysts were vitrified (n = 94), warmed (Sudano et al. 2011 Theriogenology 75, 1211–1220), and returned for 24 h of additional culture (re-expansion and hatching; hatched was evaluated 12 and 24 h after warming, respectively) when their RNA was extracted (vitrified group). The remaining embryos returned to culture until Day 8 when their RNA was extracted (fresh group). Total RNA extraction of a single blastocyst was performed using the PicoPure Kit (Applied Biosystems®, Foster City, CA, USA). The RNA samples were DNAse treated (Qiagen®, Valencia, CA, USA), and mRNA was amplified (RiboAmp Kit®). The aRNA output was evaluated with a NanoDrop (Thermo®, Wilmington, DE, USA) and Bioanalyzer (Agilent®, Santa Clara, CA, USA). Biotin-labelled and fragmented cRNA were obtained with the 3′IVT Kit (Affymetrix®, Santa Clara, CA, USA) to perform hybridization (N = 6–7, respectively, for vitrified and fresh groups) using the GeneChip Bovine Array (Affymetrix®). Microarray data analysis was performed with the FlexArray 1.6.1.1. Genes with a fold change of at least 2 and a probability of P ≤ 0.05 were considered differentially expressed. Real-time PCR was used to validate microarray results (N = 11–15, respectively, for vitrified and fresh groups). As a control, a pool of 200 blastocysts was submitted or not to mRNA amplification followed by the reverse transcription and qPCR of 17 genes. For statistical analyses, PROC GLIMMIX, PROC LOGISTIC, and PROC CORR were used. Cleavage and blastocyst production rates were 86.8 ± 1.0 and 32.5 ± 1.9%, respectively. Re-expansion and hatching/hatched rates were 69.3 and 19.3%, respectively. Messenger RNA abundance of amplified and nonamplified RNA had a high correlation (r = 0.89, P < 0.01). The microarray analysis indicated 383 differentially expressed genes (P ≤ 0.05) between fresh and vitrified blastocysts. Genes involved in apoptosis (PRDX2), heat shock (HSPA5), maternal recognition of pregnancy (IFNT2 and PAG2), and cell differentiation and placenta formation (KRT18) were downregulated in vitrified embryos. According to qPCR analysis, mRNA abundance of IFNT2, PRDX2, and KRT18 was downregulated, whereas HSPA5 mRNA levels were upregulated in vitrified blastocysts. Messenger RNA abundance of PAG2 was not different (P = 0.46) between fresh and vitrified embryos. In conclusion, vitrification alters the expression profile of the genes IFNT2, PRDX2, KRT18, and HSPA5 that can be related with embryo postcryopreservation survival capacity. FAPESP and LNBio-CNPEM are acknowledged.

Elastin-based nanoparticles for delivery of bone morphogenetic proteins

Biocompatibility, stability, and efficiency remain among the major goals in the development of new drug delivery systems. Herein we describe a facile method for encapsulation of Bone Morphogenetic Protein-2 (BMP-2) at high concentrations and in mild conditions by exploiting the thermo-responsiveness of an elastin-like polymer. Chemically synthesized poly(VPAVG) demonstrates excellent biocompatibility, stability at room temperature, and allows the use of mild conditions and harmless solvents, such as water, for its production. Here, we describe how to use a recombinantly produced poly(VPAVG) polymer to entrap BMP-2 with a high encapsulation efficiency and the methods for in vitro bioactivity assays.

89 PHENAZINE ETHOSULFATE AND FETAL CALF SERUM EFFECT IN THE ULTRASTRUCTURE AND DEVELOPMENT OF IN VITRO-PRODUCED BOVINE EMBRYOS

Over the past decades, there have been great advances in in vitro production (IVP) systems, with improved culture methods and new knowledge regarding embryo physiology, ultrastructure and morphology. Currently, the major obstacle associated with the extensive use of this technology is the great sensitivity of IVP embryos to cryopreservation. According to the literature, the reduced cryotolerance of IVP embryos is frequently associated with their high lipid content. Although is not clear until now how the lipid accumulation occurs, it may be influenced by the use of undefined culture media, supplemented with fetal calf serum (FCS); or as a result of embryo energy metabolism abnormalities that affect mitochondrial function, leading to the decrease in both the embryo quality and survival after cryopreservation. In this context, phenazine ethosulfate (PES), a reducer of NADPH electrons, which favours pentose–phosphate pathways and also inhibits the fatty acids synthesis, has been used to increase IVP embryo cryotolerance (Sudano et al. 2011 Theriogenology 75, 1211–1220). The aim of the present study was to evaluate the phenazine ethosulfate and FCS effect in the ultrastructure of IVP bovine embryos. A 2 × 2 factorial experiment design was used to test 2 FCS concentrations (0 or 10%) and the addition of PES (without or with PES) in the culture media. Slaughterhouse ovaries were used to obtain oocytes which were matured and fertilized in vitro (Day 0). Presumptive zygotes (n = 1440) were divided in 4 culture media: SOFaa without FCS; SOFaa without FCS + 0.3 μM PES (started on Day 4); SOFaa + 10% FCS; SOFaa + 10% FCS + 0.3 μM PES (started on Day 4). Embryo development was evaluated after 7 days under standard culture conditions (at 38.5°C in atmosphere of 5% O2, 5% CO2 and 90% N2). Transmission electron microscopy (TEM) was performed on Day-7 blastocysts from each group (n = 5) through standard protocol. For the statistical analysis, the arcsine transformation was applied to blastocyst percentage data and submitted to the ANOVA, followed by Tukeys' test through PROC GLM (SAS Institute Inc., Cary, NC, USA). In the absence of significant interactions, only main effect means are presented. The blastocyst production was not affected (P = 0.47) by the use of PES (42.7 ± 3.2 vs 39.3 ± 3.2, respectively for control and PES Day 4). The addition of 10% of FCS increased (P < 0.0001) the percentage of blastocysts (48.9 ± 3.2 vs 33.0 ± 3.2, respectively, for 10% and 0% of FCS). The ultrastructure analysis showed similar features in embryos from all studied groups. However, embryos cultured in the absence of FCS presented fewer and smaller lipid droplets. Moreover, embryos cultured without FCS presented more cellular debris in the perivitelinic space and in the blastocoele, indicating loss of blastomeres. The use of PES was able to reduce lipid droplets and increase the mitochondrial number in serum-produced embryos. Therefore, the PES decreased lipid content and increased mitochondrial number without affecting the development and ultrastructure of IVP bovine embryos. FAPESP 09/54513-3, 10/09922-0.

Effects of flunixin meglumine, recombinant bovine somatotropin and/or human chorionic gonadotropin on pregnancy rates in Nelore cows

The objective was to compare pharmacological strategies aiming to inhibit prostaglandin F2 alpha (PGF(2α)) synthesis (flunixin meglumine; FM), stimulate growth of the conceptus (recombinant bovine somatotropin; bST) and progesterone (P(4)) synthesis (human chorionic gonadotropin; hCG), as well as their combinations, regarding their ability to improve pregnancy rates in beef cattle. Lactating Nelore cows (N = 975), 35 to 70 days postpartum, were synchronized and inseminated by timed artificial insemination (TAI) on Day 0. On Day 7, cattle were allocated into eight groups and received one of the following treatments: saline (S) on Days 7 and 16 (Group Control); S on Day 7 and FM on Day 16 (Group FM); bST on Day 7 and S on Day 16 (Group bST); bST on Day 7 and FM on Day 16 (Group bST + FM); hCG on Day 7 and S on Day 16 (Group hCG); hCG on Day 7 and FM on Day 16 (Group hCG + FM); bST and hCG on Day 7 and S on Day 16 (Group bST + hCG), or bST and hCG on Day 7 and FM on Day 16 (Group bST + hCG + FM). The aforementioned treatments were administered at the following doses: 2.2 mg/kg FM (Banamine®; Intervet Schering-Plough, Cotia, SP, Brazil), 500 mg bST (Boostin®; Intervet Schering-Plough), and 2500 IU hCG (Chorulon®; Intervet Schering-Plough). Pregnancy diagnosis was performed 40 days after TAI by transrectal ultrasonography. Pregnancy rates were not significantly different among treatments. However, there was a main effect of hCG treatment to increase pregnancy rates (63.0 vs. 55.4%; P = 0.001). Concentrations of P(4) did not differ significantly among groups on Day 7 or on Day 16. However, consistent with the higher pregnancy rates, hCG increased P(4) concentrations on Day 16 (10.6 vs. 9.6 ng/mL, respectively; P = 0.05). We concluded that hCG treatment 7 days after TAI improved pregnancy rates of lactating Nelore cows, possibly via a mechanism leading to induction of higher P(4) concentrations, or by reducing the luteolytic stimulus during maternal recognition of pregnancy.

Renal transplantation after endovascular aortic aneurysm repair: case report and literature review

An increased number of aortic aneurysms are expected to be diagnosed in chronic renal failure patients awaiting kidney transplantation because of its strong association with atherosclerosis. The development of endovascular aortic aneurysm repair in the 1990s, which is characterized by low morbidity as well as shorter operative time and length of hospital stay, is particularly suited to these patients who are at high risk for conventional surgery. Herein we describe a case of a 58-year-old, man who was diagnosed with a 5.5-cm aortic aneurysm in 2001 and treated with a Gore Excluder (WL Gore and Assoc, Flagstaff, Ariz) aorto-iliac stent-graft. In 2004, he underwent uneventful deceased donor kidney transplantation in the right iliac fossa. With a follow-up of 6 and 9 years, respectively, there is no evidence of an endoleak. The renal function remains normal. This promising new surgical technique has been the subject of only a few published cases. At our center, endovascular aortic aneurysm repair is the first-intention treatment for these patients, as long as it is possible to preserve the iliac arteries for the renal anastomoses and the anatomic conditions are suitable for stent-graft deployment.

137 PHENAZINE ETHOSULFATE AND FETAL CALF SERUM EFFECTS ON THE DEVELOPMENT AND APOPTOSIS OF IN VITRO PRODUCED BOVINE EMBRYOS

Phenazine ethosulfate (PES) is a metabolic regulator that inhibits fatty acid synthesis and favours the pentose-phosphate pathway. Supplementation of fetal calf serum (FCS) during culture has been correlated with the reduction of quality of in vitro produced bovine embryos (IVPE). The aim of the present study was to evaluate embryo development and apoptosis in blastocysts after the supplementation of PES and FCS in culture medium of IVPE. Oocytes (N = 4320) were matured and fertilized in vitro (Day 0). The zygotes (Bos indicus) were cultured in SOFaa medium with 4 concentrations of FCS (0, 2.5, 5, and 10%) and with the use or not of 0.3 μM PES from Day 4 (after 96 h of embryo culture). Embryo development was evaluated after 7 days of culture. Apoptosis in blastocysts (N = 60–80) was accessed through TUNEL reaction. Embryos (Bos indicus) recovered from superstimulated cows were used as in vivo control (n = 15). Data were analysed by ANOVA followed by LSD using PROC GLIMMIX (SAS; SAS Institute Inc., Cary, NC, USA) means ± SEM. Increasing FCS concentration in the culture media did not change cleavage (86.7 ± 1.7, 82.3 ± 1.6, 86.3 ± 1.4, 87.0 ± 1.5, P > 0.05) and augmented blastocyst production (30.5 ± 2.5a, 41.8 ± 2.4b, 40.5 ± 2.6b, 47.2 ± 2.8b, P < 0.05), respectively, for 0, 2.5, 5, and 10%. Additionally, increasing FCS concentration increased apoptosis in blastocysts (13.8 ± 1.2b, 19.1 ± 1.8b, 20.7 ± 1.9bc, 28.4 ± 2.3c, P < 0.05, respectively, for 0, 2.5, 5, and 10%). The addition of PES from Day 4 in the culture medium did not affect (P > 0.05) cleavage (87.0 ± 1.3 and 84.4 ± 1.3), blastocyst production (42.0 ± 2.8 and 43.0 ± 2.0), and apoptosis in blastocysts (20.7 ± 2.0b and 18.9 ± 2.1b), respectively, for control and PES Day 4 groups. Independent of FCS withdrawal or PES addition to culture medium, the in vivo control group presented the lowest apoptosis rate (6.3 ± 1.1a). Therefore, increasing FCS concentration augmented embryo development and reduced blastocyst quality. However, the addition of 2.5% of FCS in the culture medium increased the embryo development without the reduction of blastocyst quality. Moreover, the PES supplementation from Day 4 did not affect embryo development and blastocyst quality. São Paulo Research Foundation – FAPESP.

Genetic, biochemical, and individual responses of the teleost fish Carassius auratus to uranium

Carassius auratus were exposed for 96 h to different concentrations of uranyl nitrate (corresponding to 0, 100, 450, and 2,025 microg U L(-1)) and killed after different postexposure periods (0, 48, and 96 h) to assess uranium bioaccumulation, peroxisome proliferation (catalase [CAT]), lipid peroxidation (thiobarbituric acid reactive substances [TBARS]), and DNA integrity in erythrocytes (comet assay). In addition, feeding behaviour was recorded as a general response to toxicant exposure. Results provided evidence of uranium bioaccumulation in muscle of C. auratus after exposure to the highest concentrations (450 and 2,025 microg U L(-1)). This tissue was able to depurate uranium to control levels 96 h after exposure ceased. However, no perturbations in feeding behaviour or cell damage were observed in the tested organisms, except for the apparent irreversible inhibition of CAT activity immediately after exposure in the highest concentration tested. Data on DNA integrity (comets) showed that waterborne uranium exposure was able to induce genotoxicity in C. auratus erythrocytes because fish exposed to all concentrations exhibited higher DNA damage than controls 96 h after exposure. No DNA damage repair was apparent throughout the postexposure period, which was contrary to a recovery scenario. This experiment provides evidence of uranium's ability to induce physiologic impairment and genotoxicity in freshwater fish at environmentally relevant concentrations.