Characterization of MPP4, a gene highly expressed in photoreceptor cells,and mutation analysis in retinitis pigmentosa

Membrane-associated guanylate kinase (MAGUK) proteins are cell-cell contact organizing molecules that mediate targeting, clustering and anchoring of proteins at synapses and other cell junctions. MAGUK proteins may contain multiple protein-protein interaction motifs including PDZ, SH3 and guanylate kinase (GuK) domains. In this study, we performed a detailed analysis of the expression pattern of MPP4, a recently described member of the MAGUK protein family. We confirmed that this gene is highly expressed in retina, and demonstrate that it is also present, at lower levels, in brain. We identified a new retina specific isoform encoding a predicted protein lacking 71 amino acids. This protein region contains a newly identified L27 domain, another module playing a role in protein-protein interaction. By RNA in situ hybridization, Mpp4 expression was found to be localized to photoreceptor cells in postnatal retina. The MPP4 gene is localized to chromosome 2, in band 2q31-33, where a locus for autosomal recessive retinitis pigmentosa (RP26) has been mapped. Mutation analysis of the entire open reading frame of the MPP4 gene in a RP26 family revealed no pathologic mutations. In addition, we did not identify mutations in a panel of 300 unrelated patients with retinitis pigmentosa.     

Bacterial lipopolysaccharide induces apoptosis in the trout ovary

Background  

In mammals it is well known that infections can lead to alterations in reproductive function. As part of the innate immune response, a number of cytokines and other immune factors is produced during bacterial infection or after treatment with lipopolysaccharide (LPS) and acts on the reproductive system. In fish, LPS can also induce an innate immune response but little is known about the activation of the immune system by LPS on reproduction in fish. Therefore, we conducted studies to examine the in vivo and in vitro effects of lipopolysaccharide (LPS) on the reproductive function of sexually mature female trout.     

The EICAT+ framework enables classification of positive impacts of alien taxa on native biodiversity

Species introduced through human-related activities beyond their native range, termed alien species, have various impacts worldwide. The IUCN Environmental Impact Classification for Alien Taxa (EICAT) is a global standard to assess negative impacts of alien species on native biodiversity. Alien species can also positively affect biodiversity (for instance, through food and habitat provisioning or dispersal facilitation) but there is currently no standardized and evidence-based system to classify positive impacts. We fill this gap by proposing EICAT+, which uses 5 semiquantitative scenarios to categorize the magnitude of positive impacts, and describes underlying mechanisms. EICAT+ can be applied to all alien taxa at different spatial and organizational scales. The application of EICAT+ expands our understanding of the consequences of biological invasions and can inform conservation decisions.

Various schemes assess negative impacts of alien species on native biodiversity, but alien species can also positively affect biodiversity. This Consensus View proposes EICAT+, a scheme which uses five semi-quantitative scenarios to categorise positive impacts, describes underlying mechanisms, and can be applied to all alien taxa and across various invasion contexts.     

The role of successional stage,vegetation type and soil disturbance in the invasion of the alien grass Cortaderia selloana

Question : This paper studies the establishment and performance of Cortaderia selloana (Pampas grass), an alien South American ornamental species that is invading many parts of the world. We asked whether (1) early successional stages were the most susceptible to C. selloana invasion; (2) soil microdisturbances increased invasion at any point of succession, and (3) C. selloana invasion of later successional stages was modulated by vegetation type Location : Delta del Llobregat (Catalonia, NE Spain). Methods : We monitored survival and growth of transplanted C. selloana seedlings in disturbed and non‐disturbed plots throughout a successional gradient with an age range of < 1 to > 10 years in different vegetation types and within the area of influence of coexisting species with similar growth form. Results : Although seedling survival was extremely low in all treatments, our results revealed that early successional stages were not the most easily invaded since we found no significant differences in the percentage survival of C. selloana along the successional gradient. However, survival and seedling bio‐mass were enhanced by soil disturbance at any seral stage. This result suggested that inhibition ruled C. selloana invasion. Invasibility neither depended on the invaded vegetation type nor on the co‐existing species with similar growth form. Finally, C. selloana invasion was not enhanced by decreasing competition with Phragmites australis, a native coexisting species because survival rates after a year were not significantly different. However, Phragmites increased C. selloana leaf length probably due to shading. Conclusions : C. selloana recruitment appears to be positively affected by soil disturbance but it is independent of successional stage or vegetation type.     

DMD Mutations in 576 Dystrophinopathy Families: A Step Forward in Genotype-Phenotype Correlations

Recent advances in molecular therapies for Duchenne muscular dystrophy (DMD) require precise genetic diagnosis because most therapeutic strategies are mutation-specific. To understand more about the genotype-phenotype correlations of the DMD gene we performed a comprehensive analysis of the DMD mutational spectrum in a large series of families. Here we provide the clinical, pathological and genetic features of 576 dystrophinopathy patients. DMD gene analysis was performed using the MLPA technique and whole gene sequencing in blood DNA and muscle cDNA. The impact of the DNA variants on mRNA splicing and protein functionality was evaluated by in silico analysis using computational algorithms. DMD mutations were detected in 576 unrelated dystrophinopathy families by combining the analysis of exonic copies and the analysis of small mutations. We found that 471 of these mutations were large intragenic rearrangements. Of these, 406 (70.5%) were exonic deletions, 64 (11.1%) were exonic duplications, and one was a deletion/duplication complex rearrangement (0.2%). Small mutations were identified in 105 cases (18.2%), most being nonsense/frameshift types (75.2%). Mutations in splice sites, however, were relatively frequent (20%). In total, 276 mutations were identified, 85 of which have not been previously described. The diagnostic algorithm used proved to be accurate for the molecular diagnosis of dystrophinopathies. The reading frame rule was fulfilled in 90.4% of DMD patients and in 82.4% of Becker muscular dystrophy patients (BMD), with significant differences between the mutation types. We found that 58% of DMD patients would be included in single exon-exon skipping trials, 63% from strategies directed against multiexon-skipping exons 45 to 55, and 14% from PTC therapy. A detailed analysis of missense mutations provided valuable information about their impact on the protein structure.     

Three-Dimensional Localization of the α and β Subunits and of the II-III Loop in the Skeletal Muscle L-type Ca2+ Channel

The L-type Ca²⁺ channel (dihydropyridine receptor (DHPR) in skeletal muscle acts as the voltage sensor for excitation-contraction coupling. To better resolve the spatial organization of the DHPR subunits (α_1s or Ca_V1.1, α₂, β_1a, δ1, and γ), we created transgenic mice expressing a recombinant β_1a subunit with YFP and a biotin acceptor domain attached to its N- and C- termini, respectively. DHPR complexes were purified from skeletal muscle, negatively stained, imaged by electron microscopy, and subjected to single-particle image analysis. The resulting 19.1-Å resolution, three-dimensional reconstruction shows a main body of 17 × 11 × 8 nm with five corners along its perimeter. Two protrusions emerge from either face of the main body: the larger one attributed to the α₂-δ1 subunit that forms a flexible hook-shaped feature and a smaller protrusion on the opposite side that corresponds to the II-III loop of Ca_V1.1 as revealed by antibody labeling. Novel features discernible in the electron density accommodate the atomic coordinates of a voltage-gated sodium channel and of the β subunit in a single docking possibility that defines the α1-β interaction. The β subunit appears more closely associated to the membrane than expected, which may better account for both its role in localizing the α_1s subunit to the membrane and its suggested role in excitation-contraction coupling.     

Buffering capacity and membrane H+ conductance of lactic acid bacteria

Abstract Buffering capacity and membrane conductance to H⁺ were measured in Enterococcus faecalis and Lactobacillus acidophilus by a pulse technique. The magnitude of these parameters varied between one species and another. Over the pH range studied, from pH 3.72 to 7.74, the acidophile Lactobacillus acidophilus showed higher values of buffering capacity and membrane H⁺ conductance than the neutrophile Enterococcus faecalis . These results support the idea that acidophiles have high cytoplasmic buffering capacity, which may allow them to resist changes in cytoplasmic pH.     

Gene-environment interactions of CETP gene variation in a high cardiovascular risk Mediterranean population

Genome-wide association studies show that cholesteryl ester transfer protein (CETP) single nucleotide polymorphisms (SNPs) are more strongly associated with HDL cholesterol (HDL-C) concentrations than any other loci across the genome. However, gene-environment interactions for clinical applications are still largely unknown. We studied gene-environment interactions between CETP SNPs and dietary fat intake, adherence to the Mediterranean diet, alcohol consumption, smoking, obesity, and diabetes on HDL-C in 4,210 high cardiovascular risk subjects from a Mediterranean population. We focused on the −4,502C>T and the TaqIB SNPs in partial linkage disequilibrium (D''= 0.88; P < 0.001). They were independently associated with higher HDL-C (P < 0.001); this clinically relevant association was greater when their diplotype was considered (14% higher in TT/B2B2 vs. CC/B1B1). No gene-gene interaction was observed. We also analyzed the association of these SNPs with blood pressure, and no clinically relevant associations were detected. No statistically significant interactions of these SNPs with obesity, diabetes, and smoking in determining HDL-C concentrations were found. Likewise, alcohol, dietary fat, and adherence to the Mediterranean diet did not statistically interact with the CETP variants (independently or as diplotype) in determining HDL-C. In conclusion, the strong association of the CETP SNPs and HDL-C was not statistically modified by diet or by the other environmental factors.     

Thalamic haemorrhage vs internal capsule-basal ganglia haemorrhage: clinical profile and predictors of in-hospital mortality

Background  

There is a paucity of clinical studies focused specifically on intracerebral haemorrhages of subcortical topography, a subject matter of interest to clinicians involved in stroke management. This single centre, retrospective study was conducted with the following objectives: a) to describe the aetiological, clinical and prognostic characteristics of patients with thalamic haemorrhage as compared with that of patients with internal capsule-basal ganglia haemorrhage, and b) to identify predictors of in-hospital mortality in patients with thalamic haemorrhage.     

Liposome-Encapsulated Bacteriophages for Enhanced Oral Phage Therapy against Salmonella spp.

Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals.