The importance of microscopic examinations of eggshells: Discrimination of bioalteration and diagenetic overprints from biological features

Although fossilization usually favors the preservation of calcium carbonate biominerals, diagenetic alterations might still produce erratic patterns that overprint the original biological structures. This investigation tries to discriminate in the fossil record “pathological” eggshells from diagenetic induced features as well as determine their origin, and aims, when possible, to provide alternative parsimonious interpretations to the origin of some of these rare and erratic features. In the past, most dinosaur eggshell studies failed to combine cathodoluminescence, scanning electron microscopy, transmitted and polarized light microscopic observations and were limited to only one or several of these examinations, which might have contributed to misinterpretations by lack of thorough observations. Sauropod eggshells from Faidella (Spain) and Auca Mahuevo (Argentina) provide ideal proxies to perform this research, as they display aberrant crystallographic features that have been or could be considered pathological. Under cathodoluminescence, the specimens fluoresce tremendously, indicating a strong diagenetic component in their make up. Guide by this information, further transmitted and polarized light microscopic examinations reveal microscopic dissolution fronts, which otherwise would have been left unnoted. The proposed hypothesis for the Faidella specimens in that organic filaments, which represent up to 2% of the shell composition, were exposed on the internal wall surfaces of pore canals where the calcium carbonate had been dissolved during a first diagenetic event. As such, the exposed extremities of the organic filaments likely triggered the formation of pseudo cores that mimic those in the membrana testacea during oogenesis. Observations based on the Argentinean specimens indicate that an added extra external structural layer is also separated from the original biological eggshell by a dissolution and recrystallization front. In addition to this abiotic process, artifact formations induced by bacterial mediation, a topic treated in an earlier publication, was also common at Auca Mahuevo. Without combined microscopic and cathodoluminiscence observations, the Faidella and Auca Mahuevo megaloolithid eggshells could be easily considered pathological eggshells. This would bias ensuing phylogenetic, paleobiological, and paleoenvironmental interpretations.A pesar de que la fosilizacion favorece la conservacion de los biominerales de carbonato calcico, las alteraciones diageneticas pueden llegar a producir patrones erraticos que se sobrepongan a las estructuras biologicas originales. Esta investigacion intenta discriminar en el registro fosil cascaras “patologicas” con rasgos diageneticamente inducidos, determinando su origen y procura, en la medida de lo posible, dar una interpretacion parsimoniosa alternativa al origen de algunos de estos rasgos extranos y erraticos. En el pasado, la mayoria de los estudios en cascaras de dinosaurios se vieron limitados al uso de uno o dos de estos procedimientos (catodoluminiscencia, microscopia electronica, observaciones con microscopio de luz transmitida y polarizada), lo que puede haber contribuido a interpretaciones erroneas debido a observaciones incompletas. Las cascaras de huevos de sauropodos del yacimiento de Faidella (Espana) y de Auca Mahuevo (Argentina) muestran condiciones ideales para realizar esta investigacion, ya que denotan rasgos critalográficos aberrantes que habían sido o podrían ser considerados como patológicos. Mediante catodoluminiscencia, los ejemplares muestran una violenta fluorescencia, lo que indica un fuerte componente diagenético en su composición. Guiados por esta informacion, los analisis posteriores con microscopia de transmision y luz polarizada revelan frentes de disoluciones microscópicas, que de otro modo no habrían sido apreciadas. La hipótesis que se propone para los ejemplares de Faidella es que filamentos orgánicos, que representan hasta el 2% de la composición de las cáscaras, estaban expuestos en las superficies de las paredes internas de los canales de los poros donde el carbonato calcico se hubo disuelto durante el primer evento diagetico. Dada esta condicion, los extremos de los filamentos orgánicos expuestos, muy probablemente dispararon la formación de pseudo núcleos que imitan los de la membrana testacea durante la oogenesis. Las observaciones basadas en los ejemplares argentinos indican que una capa externa extra esta separada de la cascara biologica original por una disolucion y recristalizacion. Ademas de este proceso abiotico, en Auca Mahuevo son tambien frecuentes rasgos inducidos por bacterias, asunto tratado en una publicacion anterior. Sin la combinacion de la combinacion de estos metodos, las cascaras de huevo de Faidella y Auca Mahuevo podrian haber sido fácilmente consideradas como patológicas, lo que sesgaría otras interpretaciones como las filogenéticas, paleobiológicas y paleoambientales

First Evidence of Reproductive Adaptation to “Island Effect” of a Dwarf Cretaceous Romanian Titanosaur, with Embryonic Integument In Ovo

<div><h3>Background</h3><p>The Cretaceous vertebrate assemblages of Romania are famous for geographically endemic dwarfed dinosaur taxa. We report the first complete egg clutches of a dwarf lithostrotian titanosaur, from Toteşti, Romania, and its reproductive adaptation to the “island effect”.</p> <h3>Methodology/Findings</h3><p>The egg clutches were discovered in sequential sedimentary layers of the Maastrichtian Sânpetru Formation, Toteşti. The occurrence of 11 homogenous clutches in successive strata suggests philopatry by the same dinosaur species, which laid clutches averaging four ∼12 cm diameters eggs. The eggs and eggshells display numerous characters shared with the positively identified material from egg-bearing level 4 of the Auca Mahuevo (Patagonia, Argentina) nemegtosaurid lithostrotian nesting site. Microscopic embryonic integument with bacterial evidences was recovered in one egg. The millimeter-size embryonic integument displays micron size dermal papillae implying an early embryological stage at the time of death, likely corresponding to early organogenesis before the skeleton formation.</p> <h3>Conclusions/Significance</h3><p>The shared oological characters between the Haţeg specimens and their mainland relatives suggest a highly conservative reproductive template, while the nest decrease in egg numbers per clutch may reflect an adaptive trait to a smaller body size due to the “island effect”. The combined presence of the lithostrotian egg and its embryo in the Early Cretaceous Gobi coupled with the oological similarities between the Haţeg and Auca Mahuevo oological material evidence that several titanosaur species migrated from Gondwana through the Haţeg Island before or during the Aptian/Albian. It also suggests that this island might have had episodic land bridges with the rest of the European archipelago and Asia deep into the Cretaceous.</p> </div

Cancer-selective, single agent chemoradiosensitising gold nanoparticles

Two nanometre gold nanoparticles (AuNPs), bearing sugar moieties and/or thiol-polyethylene glycol-amine (PEG-amine), were synthesised and evaluated for their in vitro toxicity and ability to radiosensitise cells with 220 kV and 6 MV X-rays, using four cell lines representing normal and cancerous skin and breast tissues. Acute 3 h exposure of cells to AuNPs, bearing PEG-amine only or a 50:50 ratio of alpha-galactose derivative and PEG-amine resulted in selective uptake and toxicity towards cancer cells at unprecedentedly low nanomolar concentrations. Chemotoxicity was prevented by co-administration of N-acetyl cysteine antioxidant, or partially prevented by the caspase inhibitor Z-VAD-FMK. In addition to their intrinsic cancer-selective chemotoxicity, these AuNPs acted as radiosensitisers in combination with 220 kV or 6 MV X-rays. The ability of AuNPs bearing simple ligands to act as cancer-selective chemoradiosensitisers at low concentrations is a novel discovery that holds great promise in developing low-cost cancer nanotherapeutics

Purification and Characterization of AsES Protein A Subtilisin Secreted by Acremonium Strictum is a Novel Plant Defense Elicitor.

In this work, the purification and characterization of an extracellular elicitor protein, designated AsES, produced by an avirulent isolate of the strawberry pathogen Acremonium strictum, are reported. The defense eliciting activity present in culture filtrates was recovered and purified by ultrafiltration (cutoff, 30 kDa), anionic exchange (Q-Sepharose, pH 7.5), and hydrophobic interaction (phenyl-Sepharose) chromatographies. Two-dimensional SDS-PAGE of the purified active fraction revealed a single spot of 34 kDa and pI 8.8. HPLC (C2/C18) and MS/MS analysis confirmed purification to homogeneity. Foliar spray with AsES provided a total systemic protection against anthracnose disease in strawberry, accompanied by the expression of defense-related genes (i.e. PR1 and Chi2-1). Accumulation of reactive oxygen species (e.g. H2O2 and O2̇̄) and callose was also observed in Arabidopsis. By using degenerate primers designed from the partial amino acid sequences and rapid amplification reactions of cDNA ends, the complete AsES-coding cDNA of 1167 nucleotides was obtained. The deduced amino acid sequence showed significant identity with fungal serine proteinases of the subtilisin family, indicating that AsES is synthesized as a larger precursor containing a 15-residue secretory signal peptide and a 90-residue peptidase inhibitor I9 domain in addition to the 283-residue mature protein. AsES exhibited proteolytic activity in vitro, and its resistance eliciting activity was eliminated when inhibited with PMSF, suggesting that its proteolytic activity is required to induce the defense response. This is, to our knowledge, the first report of a fungal subtilisin that shows eliciting activity in plants. This finding could contribute to develop disease biocontrol strategies in plants by activating its innate immunity

Cuidados veterinários e infeção parasitária em animais de companhia seguidos numa clínica médico-veterinária

O objetivo deste trabalho foi determinar as espécies animais que frequentam uma clínica médico-veterinária, os cuidados que os proprietários têm, os problemas mais frequentes e quais os métodos de prevenção utilizados. Pretendeu-se ainda avaliar a fauna parasitária presente em felídeos e canídeos seguidos na clínica. Em 2011, acompanharam-se 133 casos clínicos e realizaram-se 113 inquéritos a donos de animais. Efetuaram-se recolhas de fezes, num total de 86 amostras, que foram sujeitas a análises coprológicas qualitativas pela técnica de Willis. Os cães com idades entre >18 meses-6 anos, do sexo feminino, de raça pura, com porte pequeno e pelagem curta foram predominantes. Os felídeos com idade entre >18 meses-6 anos, do sexo feminino, pelagem curta e de raça indeterminada dominaram. Prevaleceram as consultas de rotina e nestas as relacionadas com a sanidade. As patologias predominantes foram do foro digestivo, urinário e dermatológico. Em cirurgia salientaram-se as esterilizações. Oito dos canídeos apresentaram ovos de Ascarididae, Ancylostomatidae e Trichuridae. Ctenocephalides felis felis, Ixodes ventalloi e R. sanguineus identificaram-se num gato e em três cães.Verificou-se que cada vez mais os proprietários têm consciência da importância do bem-estar e saúde animal como forma de proteger a sua própria saúde, levando os animais ao médico-veterinário. This study aimed to identify the more frequent pets that attend a veterinary clinic, the owners care, the main issues affecting pets, and the followed preventive measures. Simultaneously, a parasitological evaluation was performed in felines and canines attending the clinic. In 2011, 133 clinical cases were followed up and 113 enquiries performed to animal owners. Faeces were collected on pets examined in the clinic, with a total of 86 samples. Qualitative parasitological fecal analyses were performed. Dogs, aged between> 18m-6a, female, purebreds, small size and short pelage were predominant. Relatively to the cats, prevailed age between> 18m-6a, female sex, indeterminate race and short pelage. Routine visits prevailed and inside this, the appointments for sanitary issues were superior. The most frequent pathologies observed were related to the digestive and urinary systems and skin. In surgery, sterilizations were more frequent. In 8 dog faeces Ascarididae, Ancylostomatidae and Trichuridae eggs were identified. Ctenocephalides felis felis and Ixodes ventalloi and R. sanguineus were identified in three dogs and one cat. This study emphasized that owners are aware of animal welfare and animal health as a way of protection of their own health, and use to take their pets more often to a vet

The dynamical control of subduction parameters on surface topography

he long-wavelength surface deflection of Earth's outermost rocky shell is mainly controlled by large-scale dynamic processes like isostasy or mantle flow. The largest topographic amplitudes are therefore observed at plate boundaries due to the presence of large thermal heterogeneities and strong tectonic forces. Distinct vertical surface deflections are particularly apparent at convergent plate boundaries mostly due to the convergence and asymmetric sinking of the plates. Having a mantle convection model with a free surface that is able to reproduce both realistic single-sided subduction and long-wavelength surface topography self-consistently, we are now able to better investigate this interaction. We separate the topographic signal into distinct features and quantify the individual topographic contribution of several controlling subduction parameters. Results are diagnosed by splitting the topographic signal into isostatic and residual components, and by considering various physical aspects like viscous dissipation during plate bending. Performing several systematic suites of experiments, we are then able to quantify the topographic impact of the buoyancy, rheology, and geometry of the subduction-zone system to each and every topographic feature at a subduction zone and to provide corresponding scaling laws. We identify slab dip and, slightly less importantly, slab buoyancy as the major agents controlling surface topography at subduction zones on Earth. Only the island-arc high and the back-arc depression extent are mainly controlled by plate strength. Overall, his modeling study sets the basis to better constrain deep-seated mantle structures and their physical properties via the observed surface topography on present-day Earth and back through time

Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record

Fil: García, Rodolfo A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de Investigación en Paleobiología y Geología. General Roca. Río Negro; ArgentinaFil: Fernández, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. Río Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de Paleobiología y Geología. Universidad Nacional de Río Negro. Neuquén; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica. Anillaco. La Rioja; Argentin

A comparison of the radiosensitisation ability of 22 different element metal oxide nanoparticles using clinical megavoltage X-rays

Background: A wide range of nanoparticles (NPs), composed of different elements and their compounds, are being developed by several groups as possible radiosensitisers, with some already in clinical trials. However, no systematic experimental survey of the clinical X-ray radiosensitising potential of different element nanoparticles has been made. Here, we directly compare the irradiation-induced (10 Gy of 6-MV X-ray photon) production of hydroxyl radicals, superoxide anion radicals and singlet oxygen in aqueous solutions of the following metal oxide nanoparticles: Al2O3, SiO2, Sc2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, ZrO2, MoO3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb4O7, Dy2O3, Er2O3 and HfO2. We also examine DNA damage due to these NPs in unirradiated and irradiated conditions. Results: Without any X-rays, several NPs produced more radicals than water alone. Thus, V2O5 NPs produced around 5-times more hydroxyl radicals and superoxide radicals. MnO2 NPs produced around 10-times more superoxide anions and Tb4O7 produced around 3-times more singlet oxygen. Lanthanides produce fewer hydroxyl radicals than water. Following irradiation, V2O5 NPs produced nearly 10-times more hydroxyl radicals than water. Changes in radical concentrations were determined by subtracting unirradiated values from irradiated values. These were then compared with irradiation-induced changes in water only. Irradiation-specific increases in hydroxyl radical were seen with most NPs, but these were only significantly above the values of water for V2O5, while the Lanthanides showed irradiation-specific decreases in hydroxyl radical, compared to water. Only TiO2 showed a trend of irradiation-specific increase in superoxides, while V2O5, MnO2, CoO, CuO, MoO3 and Tb4O7 all demonstrated significant irradiation-specific decreases in superoxide, compared to water. No irradiation-specific increases in singlet oxygen were seen, but V2O5, NiO, CuO, MoO3 and the lanthanides demonstrated irradiation-specific decreases in singlet oxygen, compared to water. MoO3 and CuO produced DNA damage in the absence of radiation, while the highest irradiation-specific DNA damage was observed with CuO. In contrast, MnO2, Fe3O4 and CoO were slightly protective against irradiation-induced DNA damage. Conclusions: Beyond identifying promising metal oxide NP radiosensitisers and radioprotectors, our broad comparisons reveal unexpected differences that suggest the surface chemistry of NP radiosensitisers is an important criterion for their success