Mutations in tau gene exon 10 associated with FTDP-17 alter the activity of an exonic splicing enhancer to interact with Tra2 beta

Mutations in the human tau gene leading to aberrant splicing have been identified in FTDP-17, an autosomal dominant hereditary neurodegenerative disorder. Molecular mechanisms by which such mutations cause tau aberrant splicing were not understood. We characterized two mutations in exon 10 of the tau gene, N279K and Del280K. Our results revealed an exonic splicing enhancer element located in exon 10. The activity of this AG-rich splicing enhancer was altered by N279K and Del280K mutations. This exonic enhancer element interacts with human Tra2 beta protein. The interaction between Tra2 beta and the exonic splicing enhancer correlates with the activity of this enhancer element in stimulating splicing. Biochemical studies including in vitro splicing and RNA interference experiments in transfected cells support a role for Tra2 beta protein in regulating alternative splicing of human tau gene. Our results implicate the human tau gene as a target gene for the alternative splicing regulator Tra2 beta, suggesting that Tra2 beta may play a role in aberrant tau exon 10 alternative splicing and in the pathogenesis of tauopathies.     

Deltamethrin-impregnated dog collars have a potent anti-feeding and insecticidal effect on Lutzomyia longipalpis and Lutzomyia migonei

Deltamethrin-impregnated PVC dog collars were tested to assess if they were effective in protecting dogs from sand fly bites of Lutzomyia longipalpis and Lu. migonei. A protective effect against Old World species Phlebotomus perniciosus was demonstrated before. Four dogs wearing deltamethrin collars and three dogs wearing untreated collars (not impregnated with deltamethrin) were kept in separate kennels for over eight months in a village on the outskirts of Fortaleza in Ceará, Brazil. Periodically, a dog from each group was sedated, placed in a net cage for 2 h in which 150 female sand flies had been released 10-15 min before. Lu. longipalpis were used 4, 8, 12, 16, 22, 27, and 35 weeks after the attachment of the collars. Lu. migonei were used 3, 7, 11, 15, 22, 26, and 36 weeks after attachment. During 35 weeks, only 4.1% (81 of 2,022) Lu. longipalpis recovered from the nets with the deltamethrin collared dogs were engorged, an anti-feeding effect of 96%. Mortality initially was over 90% and at 35 weeks was 35% with half of the sand flies dying in the first 2 h. In contrast, 83% of the 2,094 Lu. longipalpis recovered from the nets containing the untreated collared dogs were engorged and the mortality ranged from zero to 18.8% on one occasion with 1.1% dying in the first 2 h. Similar findings were found with Lu. migonei: of 2,034 sand flies recovered over this period, only 70 were engorged, an anti-feeding effect of 96.5%, and mortality ranged from 91% initially to 46% at 36 weeks. In contrast, engorgement of controls ranged from 91 to71% and a mortality ranged from 3.5 to 29.8%. These studies show that deltamethrin impregnated collars can protect dogs against Brazilian sand flies for up to eight months. Thus, they should be useful in a program to control human and canine visceral leishmaniasis.     

A possibility of systematisation of anthropometric data of girls aged 12-15

The article describes an anthropometric cross-sectional study of 374 healthy schoolgirls aged 12-15 years from secondary schools of Tartu (Estonia). 29 body measurements and 9 skinfolds were measured. Mean skinfolds and 6 indices and ratios (including body mass index) were calculated. In each age group the data were systematized into 5 height-weight SD-classes according to the correspondence between body height and weight. The medium class lies between -0.5 SD and +0.5 SD of the respective age group mean (M +/- 0.5 SD); the other classes contain the respective outer values. All the subjects were assigned into one of the following five categories: three height/weight-concordant categories: I = small (small height-small weight), II = medium (medium height-medium weight), III = large (big height-big weight) and two height/weight-disconcordant categories: IV = so-called pyknomorphous, V = so-called leptomorphous. Categories IV and V thus contained three height/weight subclasses each. The body build categories differ significantly from each other within both groups (I-III and IV-V) in all age groups in all measured variables, except sternum length, abdomen length, trunk length, biacromial breadth, biiliocrystal breadth, femur breadth, ankle breadth, humerus breadth, wrist breadth, and head circumference for which no significant differences between pyknomorphous and leptomorphous categories were found. A multidimensional statistical model of body build might be used in girls going through puberty to systematize and compare morphological variables with other assessed characteristics in different applied studies, for example physiological, sociological, psychological, or nutritional.     

Regulation of TRKB surface expression by brain-derived neurotrophic factor and truncated TRKB isoforms

Brain-derived neurotrophic factor (BDNF) signaling through its receptor TRKB modulates survival, differentiation, and activity of neurons. BDNF activates TRKB on the cell surface, which leads to the initiation of intracellular signaling cascades and different biological responses in neurons. Neuronal activity has been shown to regulate TRKB levels on the plasma membrane of neurons, but little is known about other factors affecting TRKB surface expression levels. We report here that BDNF regulates the cell surface levels of transfected or endogenously expressed full-length TRKB, depending on the exposure time in neuroblastoma cells and primary hippocampal neurons. BDNF rapidly increases TRKB surface expression levels in seconds, whereas treatment of cells with BDNF for a longer time (minutes to hours) leads to decreased TRKB surface levels. Coexpression of the full-length TRKB together with the truncated TRKB.T1 isoform results in decreased levels of full-length TRKB on the cell surface. This effect is specific to the T1 isoform, because coexpression of a kinase-dead TRKB mutant or another kinase domain-lacking TRKB form, truncated T-Shc, leads to increased TRKB surface levels. Our results suggest that regulation of TRKB surface expression levels by different factors is tightly controlled by complex mechanisms in active neurons.     

Synthetic null-cysteine phospholamban analogue and the corresponding transmembrane domain inhibit the Ca-ATPase

Chemical synthesis, functional reconstitution, and electron paramagnetic resonance (EPR) have been used to analyze the structure and function of phospholamban (PLB), a 52-residue integral membrane protein that regulates the calcium pump (Ca-ATPase) in cardiac sarcoplasmic reticulum (SR). PLB exists in equilibrium between monomeric and pentameric forms, as observed by SDS-PAGE, EPR, and fluorescence. It has been proposed that inhibition of the pump is due primarily to the monomeric form, with both pentameric stability and inhibition dependent primarily on the transmembrane (TM) domain. To test these hypotheses, we have studied the physical and functional properties of a synthetic null-cysteine PLB analogue that is entirely monomeric on SDS-PAGE, and compared it with the synthetic null-cysteine TM domain (residues 26-52). The TM domain was found to be primarily oligomeric on SDS-PAGE, and boundary lipid spin label analysis in lipid bilayers verified that the isolated TM domain is more oligomeric than the full-length parent molecule. These results indicate that the stability of the PLB pentamer is due primarily to attractive interactions between hydrophobic TM domains, overcoming the repulsive electrostatic interactions between the cationic cytoplasmic domains (residues 1-25). When reconstituted into liposomes containing the Ca-ATPase, the null-cysteine TM domain had the same inhibitory function as that of the full-length parent molecule. We conclude that the TM domain of PLB is sufficient for inhibitory function, the oligomeric stability of PLB does not determine its inhibitory activity, and the three Cys residues in the TM domain are not required for inhibitory function.     

Feeding the extra billions: strategies to improve crops and enhance future food security

The ability to feed an expanding world population poses one of the greatest challenges to mankind in the future. Accompanying the increased demand for food by the expected nine billion inhabitants of Earth in 2050 will be a continual decrease in arable land area, together with a decline in crop yield due to a variety of stresses. For these formidable challenges to be met, future crops should not only by high-yielding, but also stress-tolerant and disease-resistant. In this review, we highlight the importance of genetic engineering as an indispensable tool to generate just such future crops. We briefly discuss strategies and available tools for biotechnological crop improvement and identify selected examples of candidate genes that may be manipulated so that current biological maxima in yield may be surpassed by comfortable margins. Future prospects and the necessity for basic research aimed at identifying novel target genes are also discussed.     

Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score

Introduction  

Frequent assessments of rheumatoid arthritis (RA) disease activity allow timely adaptation of therapy, which is essential in preventing disease progression. However, values of acute phase reactants (APRs) are needed to calculate current composite activity indices, such as the Disease Activity Score (DAS)28, the DAS28-CRP (i.e. the DAS28 using C-reactive protein instead of erythrocyte sedimentation rate) and the Simplified Disease Activity Index (SDAI). We hypothesized that APRs make limited contribution to the SDAI, and that an SDAI-modification eliminating APRs – termed the Clinical Disease Activity Index (CDAI; i.e. the sum of tender and swollen joint counts [28 joints] and patient and physician global assessments [in cm]) – would have comparable validity in clinical cohorts.     

Aspects of early arthritis. Traditional DMARD therapy: is it sufficient?

There is increasing evidence for beneficial effects of early DMARD (disease-modifying antirheumatic drug) therapy over delayed treatment in patients who present with arthritis of recent onset. However, no universal consensus exists concerning the choice of initial drug or whether single drugs or combinations should be given as initial treatments. Recent studies have focused on the benefits of various strategies in which treatments were tailored to achieve low levels of disease activity, as assessed using validated response criteria. These studies demonstrated superiority of 'aggressive' over 'conventional' approaches. Whether the inclusion of tumour necrosis factor antagonists or other biologic targeted therapies in such strategies confers additional benefits in terms of improved long-term outcomes must be clarified by further studies. Assessment of risks in the individual patient, allowing individual 'tailoring' of the initial treatment, would be desirable.     

Validation of the International Classification of Functioning, Disability and Health (ICF) Core Set for rheumatoid arthritis from the patient perspective using focus groups

Functioning is recognized as an important study outcome in rheumatoid arthritis (RA). The Comprehensive ICF Core Set for RA is an application of the International Classification of Functioning, Disability and Health (ICF) of the World Health Organisation with the purpose of representing the typical spectrum of functioning of patients with RA. To strengthen the patient perspective, persons with RA were explicitly involved in the validation of the Comprehensive ICF Core Set for RA using qualitative methodology. The objective of the study was twofold: to come forward with a proposal for the most appropriate methodology to validate Comprehensive ICF Core Sets from the patient perspective; and to add evidence to the validation of the Comprehensive ICF Core Set for RA from the perspective of patients. The specific aims were to explore the aspects of functioning and health important to patients with RA using two different focus group approaches (open approach and ICF-based approach) and to examine to what extent these aspects are represented by the current version of the Comprehensive ICF Core Set for RA. The sampling of patients followed the maximum variation strategy. Sample size was determined by saturation. The focus groups were digitally recorded and transcribed verbatim. The meaning condensation procedure was used for the data analysis. After qualitative data analysis, the resulting concepts were linked to ICF categories according to established linking rules. Forty-nine patients participated in ten focus groups (five in each approach). Of the 76 ICF categories contained in the Comprehensive ICF Core Set for RA, 65 were reported by the patients based on the open approach and 71 based on the ICF-based approach. Sixty-six additional categories (open approach, 41; ICF-based approach, 57) that are not covered in the Comprehensive ICF Core Set for RA were raised. The existing version of the Comprehensive ICF Core Set for RA could be confirmed almost entirely by the two different focus group approaches applied. Focus groups are a highly useful qualitative method to validate the Comprehensive ICF Core Set for RA from the patient perspective. The ICF-based approach seems to be the most appropriate technique.