Common variants at 9p21 and 8q22 are associated with increased susceptibility to optic nerve degeneration in glaucoma

Optic nerve degeneration caused by glaucoma is a leading cause of blindness worldwide. Patients affected by the normal-pressure form of glaucoma are more likely to harbor risk alleles for glaucoma-related optic nerve disease. We have performed a meta-analysis of two independent genome-wide association studies for primary open angle glaucoma (POAG) followed by a normal-pressure glaucoma (NPG, defined by intraocular pressure (IOP) less than 22 mmHg) subgroup analysis. The single-nucleotide polymorphisms that showed the most significant associations were tested for association with a second form of glaucoma, exfoliation-syndrome glaucoma. The overall meta-analysis of the GLAUGEN and NEIGHBOR dataset results (3,146 cases and 3,487 controls) identified significant associations between two loci and POAG: the CDKN2BAS region on 9p21 (rs2157719 [G], OR = 0.69 [95%CI 0.63–0.75], p = 1.86×10⁻¹⁸), and the SIX1/SIX6 region on chromosome 14q23 (rs10483727 [A], OR = 1.32 [95%CI 1.21–1.43], p = 3.87×10⁻¹¹). In sub-group analysis two loci were significantly associated with NPG: 9p21 containing the CDKN2BAS gene (rs2157719 [G], OR = 0.58 [95% CI 0.50–0.67], p = 1.17×10⁻¹²) and a probable regulatory region on 8q22 (rs284489 [G], OR = 0.62 [95% CI 0.53–0.72], p = 8.88×10⁻¹⁰). Both NPG loci were also nominally associated with a second type of glaucoma, exfoliation syndrome glaucoma (rs2157719 [G], OR = 0.59 [95% CI 0.41–0.87], p = 0.004 and rs284489 [G], OR = 0.76 [95% CI 0.54–1.06], p = 0.021), suggesting that these loci might contribute more generally to optic nerve degeneration in glaucoma. Because both loci influence transforming growth factor beta (TGF-beta) signaling, we performed a genomic pathway analysis that showed an association between the TGF-beta pathway and NPG (permuted p = 0.009). These results suggest that neuro-protective therapies targeting TGF-beta signaling could be effective for multiple forms of glaucoma.     

Regional and cell-type-specific effects of DAMGO on striatal D1 and D2 dopamine receptor-expressing medium-sized spiny neurons

The striatum can be divided into the DLS (dorsolateral striatum) and the VMS (ventromedial striatum), which includes NAcC (nucleus accumbens core) and NAcS (nucleus accumbens shell). Here, we examined differences in electrophysiological properties of MSSNs (medium-sized spiny neurons) based on their location, expression of DA (dopamine) D1/D2 receptors and responses to the μ-opioid receptor agonist, DAMGO {[D-Ala²-MePhe⁴-Gly(ol)⁵]enkephalin}. The main differences in morphological and biophysical membrane properties occurred among striatal sub-regions. MSSNs in the DLS were larger, had higher membrane capacitances and lower Rin (input resistances) compared with cells in the VMS. RMPs (resting membrane potentials) were similar among regions except for D2 cells in the NAcC, which displayed a significantly more depolarized RMP. In contrast, differences in frequency of spontaneous excitatory synaptic inputs were more prominent between cell types, with D2 cells receiving significantly more excitatory inputs than D1 cells, particularly in the VMS. Inhibitory inputs were not different between D1 and D2 cells. However, MSSNs in the VMS received more inhibitory inputs than those in the DLS. Acute application of DAMGO reduced the frequency of spontaneous excitatory and inhibitory postsynaptic currents, but the effect was greater in the VMS, in particular in the NAcS, where excitatory currents from D2 cells and inhibitory currents from D1 cells were inhibited by the largest amount. DAMGO also increased cellular excitability in the VMS, as shown by reduced threshold for evoking APs (action potentials). Together the present findings help elucidate the regional and cell-type-specific substrate of opioid actions in the striatum and point to the VMS as a critical mediator of DAMGO effects.     

Morpho-anatomical differentiation of Suaeda maritima (L.) Dumort. 1827. (Chenopodiaceae) populations from inland and maritime saline area

Morphological analysis of four populations of Suaeda maritima was undertaken in order to examine the variation between populations from inland and maritime saline area, as well as between the two subspecies. Variability and significance of morpho-anatomical differentiation were examined using principal component analysis (PCA), discriminant component analysis (DCA) and cluster analysis. Plants of each population exhibited halomorphic and xeromorphic characteristics. The results of PCA and DCA showed that S. maritima subsp. prostrata and S. maritima subsp. maritima could be clearly separated based on their quantitative anatomical characteristics. Based on our analysis, climate and the amount of salt and ions in the soil, are important factors that enhance the adaptive potential of S. maritima.     

Identification of lipopeptide antibiotics of a <Emphasis Type="Italic">Bacillus subtilis</Emphasis> isolate and their control of <Emphasis Type="Italic">Fusarium graminearum</Emphasis> diseases in maize and wheat

Substances produced by Bacillus subtilis D1/2, a bacterium isolated from cultivated soil, were found to inhibit Fusarium graminearum. The antifungal activity of the bacterium was attributable to major extracellular lipopeptides isolated and identified as fengycins. Their synthesis was enhanced by casamino acids added to the culture medium. The unpurified cell-free spent medium elicited hemolysis with increasing concentration. Its application to field-cultivated maize and chamber-grown wheat suppressed gibberella ear rot and Fusarium head blight, respectively, when the plants were inoculated with F. graminearum macroconidia. The treatment of maize ears consistently arrested ear-rot development, while the treatment of wheat spikes retarded the progress of Fusarium head blight. Although the deoxynivalenol and ergosterol contents of treated maize kernels were halved, they remained high because of the experimental requirement to inoculate with a high number (1.5 × 10⁴) of macroconidia. As a potential antifungal agent for controlling Fusarium diseases, B. subtilis D1/2 can be further developed as a useful component of integrated pest management. Handling Editor: Reijo Karjalainen.     

Trypanosoma cruzi: Genetic diversity influences the profile of immunoglobulins during experimental infection

The clonal evolution model postulated for Trypanosoma cruzi predicts a correlation between the phylogenetic divergence of T. cruzi clonal genotypes and their biological properties. In the present study, the linkage between phylogenetic divergence of the parasite and IgG, IgG1, IgG2a and IgG2b response has been evaluated during the acute and chronic phases of the experimental infection. Eight laboratory-cloned stocks representative of this phylogenetic diversity and including the lineages T. cruzi I (genotypes 19 and 20), T. cruzi II (genotype 32) and T. cruzi (genotype 39) have been studied. The results showed that the pattern of humoral immune response was correlated with T. cruzi genotype, and that stocks included in genotype 20 were responsible for the high IgG response in the acute and chronic phases. Moreover, T. cruzi I lineage was more efficient in over-expressing all subclasses of specific anti-parasite IgG than either T. cruzi II or T. cruzi lineages. Curiously, the alteration in the pattern of antibodies induced by Benznidazole treatment was related to the phase of the infection but not to the genotype of the parasite. The data suggest that genotypes of T. cruzi are able to drive levels/subclasses of specific IgG, hence giving rise to further concerns about the sensitivity of serological assays in the diagnosis of human Chagas disease.     

Non-invasive microelectrode ion flux measurements to study adaptive responses of microorganisms to the environment

The regulation of membrane-transport activity is crucial for intracellular pH homeostasis, maintenance of cell osmotic potential, nutrient acquisition, signalling, and adaptation of bacterial cells. The non-invasive microelectrode ion flux estimation (MIFE) technique is a powerful tool for kinetic studies of membrane-transport processes across cellular membranes. Since 2001, when this technique was first applied to the study of membrane-transport processes in bacterial cells (J Microbiol Methods 46, 119-129), a large amount of information has been accumulated. This review summarizes some of these findings and discusses the advantages and applicability of this technique in studying bacterial adaptive responses to adverse environmental conditions. First, various methodological aspects of the application of this novel technique in microbiology are discussed. Then, several practical examples ('case studies') are described. The latter include changes in membrane-transport activity in response to various stresses (acidic, osmotic, and temperature stresses) as well as flux changes as a function of bacterial growth stage and nutrient availability. It is shown that non-invasive ion flux measurements may provide a significant conceptual advance in our understanding of adaptive responses in bacteria, fungi and biofilms to a variety of environmental conditions. The technique can also be used for the rapid assessment of food-processing treatments aimed at reducing bacterial contamination of food and for the development of strategies to assess the resistance of organisms to antimicrobial agents.     

Extracellular Ca2+ ameliorates NaCl-induced K+ loss from Arabidopsis root and leaf cells by controlling plasma membrane K+ -permeable channels

Calcium can ameliorate Na+ toxicity in plants by decreasing Na+ influx through nonselective cation channels. Here, we show that elevated external [Ca2+] also inhibits Na+ -induced K+ efflux through outwardly directed, K+ -permeable channels. Noninvasive ion flux measuring and patch-clamp techniques were used to characterize K+ fluxes from Arabidopsis (Arabidopsis thaliana) root mature epidermis and leaf mesophyll under various Ca2+ to Na+ ratios. NaCl-induced K+ efflux was not related to the osmotic component of the salt stress, was inhibited by the K+ channel blocker TEA+, was not mediated by inwardly directed K+ channels (tested in the akt1 mutant), and resulted in a significant decrease in cytosolic K+ content. NaCl-induced K+ efflux was partially inhibited by 1 mm Ca2+ and fully prevented by 10 mm Ca2+. This ameliorative effect was at least partially attributed to a less dramatic NaCl-induced membrane depolarization under high Ca2+ conditions. Patch-clamp experiments (whole-cell mode) have demonstrated that two populations of Ca2+ -sensitive K+ efflux channels exist in protoplasts isolated from the mature epidermis of Arabidopsis root and leaf mesophyll cells. The instantaneously activating K+ efflux channels showed weak voltage dependence and insensitivity to external and internal Na+. Another population of K+ efflux channels was slowly activating, steeply rectifying, and highly sensitive to Na+. K+ efflux channels in roots and leaves showed different Ca2+ and Na+ sensitivities, suggesting that these organs may employ different strategies to withstand salinity. Our results suggest an additional mechanism of Ca2+ action on salt toxicity in plants: the amelioration of K+ loss from the cell by regulating (both directly and indirectly) K+ efflux channels.     

Physical fitness, menstrual cycle disorders and smoking habit in Croatian National Ballet and National Folk Dance Ensembles

The study investigated differences in morphological, motor and functional abilities between folk and ballet dancers. The sample comprised 51 female subjects: Croatian National Ballet (N=30) and Croatian National Folk Ensemble "LADO" (N=21). The data regarding menstrual cycle, menarche, number of births and smoking habit were collected and the morphological, motor and functional abilities measured. Significant correlations between the amount of fat tissue and number of births were found in both groups. Folk dancers were as tall as ballet dancers but weighted more and had a larger body frame (p<0.001). Ballet dancers were more flexible but there were no differences in absolute maximal oxygen uptake (2.65 vs. 2.35 L/min, p=0.101). Still, as the ballet dancers weighted less, their relative maximal oxygen uptake was significantly higher (37.62 vs. 50.22 mL/kg/min, p<0.001). Also, a high number of 45% of smokers among professional ballet and professional folk dancers was found.