Tau hyperphosphorylation and increased BACE1 and RAGE levels in the cortex of PPARβ/δ-null mice

The role of peroxisome proliferator activator receptor (PPAR)β/δ in the pathogenesis of Alzheimer's disease has only recently been explored through the use of PPARβ/δ agonists. Here we evaluated the effects of PPARβ/δ deficiency on the amyloidogenic pathway and tau hyperphosphorylation. PPARβ/δ-null mice showed cognitive impairment in the object recognition task, accompanied by enhanced DNA-binding activity of NF-κB in the cortex and increased expression of IL-6. In addition, two NF-κB-target genes involved in β-amyloid (Aβ) synthesis and deposition, the β site APP cleaving enzyme 1 (Bace1) and the receptor for advanced glycation endproducts (Rage), respectively, increased in PPARβ/δ-null mice compared to wild type animals. The protein levels of glial fibrillary acidic protein (GFAP) increased in the cortex of PPARβ/δ-null mice, which would suggest the presence of astrogliosis. Finally, tau hyperphosphorylation at Ser199 and enhanced levels of PHF-tau were associated with increased levels of the tau kinases CDK5 and phospho-ERK1/2 in the cortex of PPARβ/δ^?/? mice.Collectively, our findings indicate that PPARβ/δ deficiency results in cognitive impairment associated with enhanced inflammation, astrogliosis and tau hyperphosphorylation in the cortex.     

Capgras syndrome: a proposal of neuropsychological battery for assessment

Capgras syndrome is the most prevalent of the delusional misidentification syndromes. It appears in both psychiatric illness and organic brain damage. Cognitive and neuropsychiatric models (lateralization and disconnection) have been proposed to explain the syndrome. From a neuropsychological point of view Capgras syndrome seems to be due to damage of bifrontal and right limbic and temporal regions. Memory, feeling of familiarity, monitoring of self and reality would be altered. All of these cause a failure to adequately integrate the information about emotions and facial recognition. Relative preservation of the left frontal lobe may be necessary for the development of delusional response. There does not seem to be a differential pattern as regards the aetiology, but there is a common underlying neuropsychiatric mechanism. Based on theoretic models, and clinics features, we propose a neuropsychological battery to assess the Capgras syndrome, that should be sensitive to the main expected deficits.     

Ecology matters: Atlantic-Mediterranean disjunction in the sand-dune shrub Armeria pungens (Plumbaginaceae)

Inferring the evolutionary history of Mediterranean plant lineages from current genetic, distributional and taxonomic patterns is complex because of a number of palaeoclimatic and geological interconnected factors together with landscape heterogeneity and human influence. Therefore, choosing spatially simplified systems as study groups is a suitable approach. An amplified fragment length polymorphism (AFLP) study using two restriction enzyme combinations (EcoRI/MseI and KpnI/MseI) was carried out to estimate the structure of genetic variation throughout the range of Armeria pungens. This species has a West Iberian-Corso/Sardinian disjunct distribution on coastal sand-dune ecosystems. Bayesian, amova and genetic distance analyses of the AFLP data revealed the same distinguishable genetic groups, which do not match the main geographical disjunction. Corso-Sardinian populations were found to be genetically closer to southwest Portuguese than to those from the Gulf of Cadiz (the closest geographically). Eastwards long-distance dispersal is therefore invoked to explain this geographical disjunction. A GIS analysis based on bioclimatic envelope modelling aiming to characterize the current locations of A. pungens found strong similarities between the Portugal and Corsica-Sardinia sites and less so between these areas and the Gulf of Cadiz. This coincident pattern between AFLP and climatic data suggests that the geographical disjunction is better explained by climatic factors than by the likeliness of a stochastic dispersal event. Such a combined phylogeographical-GIS modelling approach proves to be enlightening in reconstructing the evolutionary history of plant species.     

The trans-sialidase from Trypanosoma cruzi efficiently transfers alpha-(2-->3)-linked N-glycolylneuraminic acid to terminal beta-galactosyl units

The trans-sialidase from Trypanosoma cruzi (TcTS), the agent of Chagas' disease, is a unique enzyme involved in mammalian host-cell invasion. Since T. cruzi is unable to synthesize sialic acids de novo, TcTS catalyzes the transfer of alpha-(2-->3)-sialyl residues from the glycoconjugates of the host to terminal beta-galactopyranosyl units present on the surface of the parasite. TcTS also plays a key role in the immunomodulation of the infected host. Chronic Chagas' disease patients elicit TcTS-neutralizing antibodies that are able to inhibit the enzyme. N-Glycolylneuraminic acid has been detected in T. cruzi, and the trans-sialidase was pointed out as the enzyme involved in its incorporation from host glycoconjugates. However, N-glycolylneuraminic acid alpha-(2-->3)-linked-containing oligosaccharides have not been analyzed as donors in the T. cruzi trans-sialidase reaction. In this paper we studied the ability of TcTS to transfer N-glycolylneuraminic acid from Neu5Gc(alpha2-->3)Gal(beta1-->4)GlcbetaOCH(2)CH(2)N(3) (1) and Neu5Gc(alpha2-->3)Gal(beta1-->3)GlcNAcbetaOCH(2)CH(2)N(3) (2) to lactitol, N-acetyllactosamine and lactose as acceptor substrates. Transfer from 1 was more efficient (50-65%) than from 2 (20-30%) for the three acceptors. The reactions were inhibited when the enzyme was preincubated with a neutralizing antibody. K(m) values were calculated for 1 and 2 and compared with 3'-sialyllactose using lactitol as acceptor substrate. Analysis was performed by high-performance anion-exchange (HPAEC) chromatography. A competitive transfer reaction of compound 1 in the presence of 3'-sialyllactose and N-acetyllactosamine showed a better transfer of Neu5Gc than of Neu5Ac.     

Scaled-up biotechnological production of individual betalains in a microbial system

The recent interest in plant pigment betalains as bioactive compounds and chemopreventive agents has led to the search for a reliable and scalable process to obtain them. The cloning of the novel and efficient enzyme 4,5-DOPA-extradiol dioxygenase from Gluconacetobacter diazotrophicus in an expression vector, and the subsequent heterologous expression in Escherichia coli cultures has led to the start-up of a biotechnological production system of individual pigments. The aim of this study was to search for the optimal conditions for the production of betalamic acid in microbial factories and the scaled-up obtention of the derived pigments. Four different betaxanthins and two betacyanins were obtained after the addition of non-transformable amines and amino acids and their condensation with the betalamic acid produced by the dioxygenase. The scaled-up obtention and purification of betalains improved the yields of the previous methodologies reaching quantities by up to 150 mg of pure compounds.     

A recombinant functional variant of the olive pollen allergen Ole e 10 expressed in baculovirus system

Pollens have been reported as important sources of antigens causing type-I allergy and, among them, olive pollen has high clinical relevance in Mediterranean countries. The most recently described olive allergen, Ole e 10, is involved in cross-reactivity phenomena and related to asthma induction in allergic patients. These immunologic features make this allergen a good candidate to be included in diagnosis and therapy of protocols of allergic diseases. Since the availability of Ole e 10 from the olive pollen is limited, the allergen has been efficiently expressed in the baculovirus/insect cell system. The Ole e 10-cDNA inserted into the transfer vector pBacPAK8 allowed the expression of the recombinant protein in cultured Sf21 cells. Recombinant Ole e 10 (rOle e 10) was purified from the culture after dialysis and three chromatographic steps. Mass spectrometry, Edman degradation, IgE- and IgG-binding analyses were employed to characterize the recombinant allergen, which showed molecular and immunological equivalence with the natural protein. Affinity gel electrophoresis in presence of laminarin (1,3-beta-glucan) revealed that rOle e 10 retains identical carbohydrate-binding capacity than the natural allergen. In conclusion, the recombinant expression of Ole e 10 in baculovirus/insect cell system produces a homogeneous and biologically active allergen that could be useful for clinical and scientific purposes.     

Solution structure of the C-terminal domain of Ole e 9, a major allergen of olive pollen

Ole e 9 is an olive pollen allergen belonging to group 2 of pathogenesis-related proteins. The protein is composed of two immunological independent domains: an N-terminal domain (NtD) with 1,3-beta-glucanase activity, and a C-terminal domain (CtD) that binds 1,3-beta-glucans. We have determined the three-dimensional structure of CtD-Ole e 9 (101 amino acids), which consists of two parallel alpha-helices forming an angle of approximately 55 degrees , a small antiparallel beta-sheet with two short strands, and a 3-10 helix turn, all connected by long coil segments, resembling a novel type of folding among allergens. Two regions surrounded by aromatic residues (F49, Y60, F96, Y91 and Y31, H68, Y65, F78) have been localized on the protein surface, and a role for sugar binding is suggested. The epitope mapping of CtD-Ole e 9 shows that B-cell epitopes are mainly located on loops, although some of them are contained in secondary structural elements. Interestingly, the IgG and IgE epitopes are contiguous or overlapped, rather than coincident. The three-dimensional structure of CtD-Ole e 9 might help to understand the underlying mechanism of its biochemical function and to determine possible structure-allergenicity relationships.     

Chemical composition and antimicrobial activity of Citrus essences on honeybee bacterial pathogen <Emphasis Type="Italic">Paenibacillus larvae</Emphasis>, the causal agent of American foulbrood

Antimicrobial properties and chemical composition of four citrus fruit essential oils to control Paenibacillus larvae, the causal agent of American foulbrood disease (AFB) were determined. This honeybee larvae disease occurs throughout the world and is found in many beekeeping areas of Argentina. Citrus fruit essential oils tested were those from grapefruit (Citrus paradisi), sweet orange (Citrus sinensis), mandarin (Citrus nobilis) and lemon (Citrus limon). The components of the essential oils were identified by SPME-GC/MS analysis. The antimicrobial activity of the oils against P. larvae were determined by the broth microdilution method. Two way ANOVA tests for minimum inhibitory concentrations (MICs) data and minimal bactericide concentrations (MBCs) data, indicated significant differences between the strains and the oils tested. The antimicrobial assays showed that the oil of C. paradisi inhibited the bacterial strains at the lowest concentrations tested, MICs and MBCs averages of 385.0 mg/l and 770.0 mg/l, respectively. This property could be attributed to the kind and percentage of the volatile components of the oil, like limonene (69.9%) and myrcene (9.6%). The use of essential oils or their specific volatile components individually against pests related to food provision may represent an alternative scope for the control of this serious disease because it does not leave toxic chemical residues in honey nor in its by products.