Use of Okadaic Acid to Identify Relevant Phosphoepitopes in Pathology: A Focus on Neurodegeneration

Protein phosphorylation is involved in the regulation of a wide variety of physiological processes and is the result of a balance between protein kinase and phosphatase activities. Biologically active marine derived compounds have been shown to represent an interesting source of novel compounds that could modify that balance. Among them, the marine toxin and tumor promoter, okadaic acid (OA), has been shown as an inhibitor of two of the main cytosolic, broad-specificity protein phosphatases, PP1 and PP2A, thus providing an excellent cell-permeable probe for examining the role of protein phosphorylation, and PP1 and PP2A in particular, in any physiological or pathological process. In the present work, we review the use of okadaic acid to identify specific phosphoepitopes mainly in proteins relevant for neurodegeneration. We will specifically highlight those cases of highly dynamic phosphorylation-dephosphorylation events and the ability of OA to block the high turnover phosphorylation, thus allowing the detection of modified residues that could be otherwise difficult to identify. Finally, its effect on tau hyperhosphorylation and its relevance in neurodegenerative pathologies such as Alzheimer’s disease and related dementia will be discussed.     

Drivers of grassland loss in Hungary during the post-socialist transformation (1987–1999)

The increase in the speed of land-cover change experienced worldwide is becoming a growing concern. Major socio-economic transitions, such as the breakdown of socialism in Europe, may lead to particularly high rates of landscape transformations. In this paper we examined the loss of semi-natural grasslands in Hungary between 1987 and 1999. We studied the relationship between 9 potential driving forces and the fate of grasslands using logistic GLMs. Grassland loss was found to be very high (1.31 % per year), which is far higher than either before or after this period. The most influential predictors of grassland loss were environmental and landscape characteristics (soil type, area of remnant grassland patches), and the socio-economic context (distance to paved road, and nearest settlement, human population density). Several processes and relationships can only be understood from a historical perspective (e.g. large extent of afforestation, strong decrease of soil water table). Grassland loss during the study period emerged as a consequence of survival strategies of individual farmers seeking adaptation to the changing environmental and socio-economic conditions, and not urbanization and agricultural intensification which are the main underlying drivers for the ongoing landscape transformations in most parts of the developed world. Though globalization increasingly influences local land use decisions, reconstructing and modelling recent landscape changes cannot be done without a proper understanding of local history and culture. Our analysis shows the importance of large-area yet high resolution landscape change research, which may reveal unexpected patterns of land cover change, undetected at coarser scales.     

Do vegetative and reproductive phenophases of deciduous tropical spe-cies respond similarly to rainfall pulses?

Deciduous trees with high-density wood that occur in dry seasonal tropical regions respond to rainfall seasonality with synchrony in phenophases. However, they may exhibit interannual differences in sy...     

Intensity and timing of warming and drought differentially affect growth patterns of co-occurring Mediterranean tree species

Climate change involves warmer temperatures, altered precipitation patterns, increased climatic variability and, in Mediterranean regions, increased frequency and severity of droughts. Tree species may show different growth responses to these components of climatic change, which may trigger changes in forest composition and dominance. We assessed the influence of recent climatic changes on secondary growth of mature trees from four species co-occurring in a Mediterranean continental forest: Quercus ilex, Quercus faginea, Pinus nigra and Juniperus thurifera. We used dendrochronology to relate radial-growth variables [earlywood and latewood widths, basal area increment (BAI)] to annual and seasonal climatic variables for the period 1977–2007. Our results showed that Q. faginea BAI has declined, whereas J. thurifera BAI has increased over time while Q. ilex and P. nigra have maintained their growth rates. Growth was mainly favored by higher precipitations and tree size for all species. Reduced growth during extremely dry years was observed for all study species, but all of them except Q. faginea recovered their growth levels 2 years after drought. Our findings illustrate how the effects of climatic changes on growth should include analyses of seasonal climatic trends and extreme events such as severe droughts. We conclude that the seasonal timing of warming and precipitation alterations leading to drought events caused contrasting effects on growth of co-occurring Mediterranean tree species, compromising their future coexistence.     

Soil C and N dynamics, nutrient leaching and fertility in a pine plantation amended with wood ash under Mediterranean climate

Wood ash addition to forest soils can balance exported nutrients by tree harvesting and decrease soil acidity, but its effectiveness in Mediterranean areas has been scarcely evaluated. The aim of the present study was to assess the effects of wood ash application on soil C and N dynamics, nutrient leaching and fertility in a pine stand. Treatments were loose and pelleted ash application (11 Mg ha^?1), alone or combined with N fertilizer, and a control treatment. Nutrient leaching and soil chemical and biological properties were periodically evaluated for a 30-month period. Wood ash increased leaching of base cations (Ca, Mg, Na and K) and P, mainly at the beginning of the study. The effect was more pronounced for the loose formulation. As a consequence, a positive effect on soil nutrient availability (exchangeable base cations and extractable P) and soil acidity reduction was observed for the loose formulation in the 0–10-cm soil layer. Carbon and N dynamics were only affected when ash was applied with N fertilizer, which enhanced CO₂ flux during the study period.     

Acute toxicity in laboratory tests of fresh and aged residues of pesticides used in citrus on the parasitoid Aphytis melinus

California red scale Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) is a worldwide citrus key pest. One of the control strategies currently promoted in the Mediterranean basin is the augmentative release of the parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae). A clear understanding of the impact that pesticides commonly used in citrus have on this parasitoid is therefore essential to assure the efficacy of the method. The aims of this study were to evaluate the lethal effects of freshly applied and laboratory-aged residues of eighteen selected pesticides recommended in IPM for citrus on A. melinus adults. According to their toxicity on A. melinus, the pesticides could be divided in four groups. Etofenprox and chlorpyrifos were harmful and persistent; abamectin was moderately harmful and slightly persistent; dimethoate, chlorpyrifos-methyl, and spirodiclofen were slightly harmful and moderately persistent; and azadirachtin, etoxazole, fenbutaestan, hexythiazox, mancozeb, petroleum oil, pirimicarb, propargite, pymetrozine, pyriproxyfen, spirotetramat, and tebufenpyrad were considered harmless. The information presented here will help us to integrate A. melinus release within an IPM for citrus in which pesticides are still used.     

Atypical non-progressive pneumonia in goats

An outbreak of severe respiratory disease in a goat herd was associated with Mycoplasma ovipneumoniae, Mycoplasma arginini, Mannheimia haemolytica and Pasteurella multocida with mortality rates exceeding 20% in kids. Post mortem features in affected kids included severe pleuropneumonia, lung consolidation, large quantities of pleural fluid and pericarditis. This is the first report of atypical proliferative pneumonia in goats in Portugal.     

Description of original endoscopic findings and respiratory functional assessment using barometric whole-body plethysmography in dogs suffering from brachycephalic airway obstruction syndrome

The clinical features of brachycephalic airway obstructive disease in 11 brachycephalic dogs are described in this study. The respiratory strategy was assessed before (n=11) and after (n=6) surgery using barometric whole-body plethysmography (BWBP), with the relationship between BWBP variables and the severity of the clinical signs assessed by the use of a respiratory score based on clinical, radiographic and endoscopic findings. Partial collapse of the left main bronchus was a common finding not previously described as part of the brachycephalic airway obstructive disease syndrome. Epiglottic cysts, laryngeal granulomas and nasopharyngeal turbinates in English Bulldogs were other previously unreported findings. No significant correlation between the respiratory score and any of the BWBP variables was detected. Compared to healthy dogs, brachycephalic dogs had a significantly lower Te/Ti ratio (expiratory time over inspiratory time), peak inspiratory flow (PIF) per kg bodyweight (BW), significantly higher peak expiratory flow (PEF) per kgBW, PEF/PIF, and enhanced pause. These variations are compatible with upper airway obstructions primarily in the extrathoracic airways. Following surgery, a significant decrease in PEF/PIF was detected. The study showed that BWBP could be used to characterise the respiratory strategy in brachycephalic dogs before and after surgery.     

Rabbits' eye globe sonographic biometry

Objective To measure intraocular structures in New Zealand White breed rabbits (Oryctolagus cuniculus Linnaeus, 1758) using A‐mode and B‐mode ultrasound with a 20 MHz transducer. Procedures In this study, the eyes of 15 rabbits were evaluated for determination of intraocular measurements using an ophthalmic ultrasound unit able to operate in both A and B‐modes. The distances from the cornea to the anterior capsule of the lens (D1), from the anterior capsule of the lens to the posterior capsule of the lens (D2), from the posterior capsule of the lens to the retina (D3) and the complete length of the eye, which corresponds to the distance from the cornea to the retina (D4) were taken. Results The mean values obtained were 2.70 mm (±0.22 mm) for D1, 7.32 mm (±0.40 mm) for D2, 7.10 mm (±0.45 mm) for D3 and 17.12 mm (±0.41 mm) for D4. Statistical analyses using the Student’s t‐test showed that there were no differences between the eyes. Conclusions The study was feasible without the need of pharmacological restraint and yielded normal mean values for ocular sonographic biometry in rabbits.