Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS

This study aims at substituting the essential functions of photoreceptors in patients who are blind owing to untreatable forms of hereditary retinal degenerations. A microelectronic neuroprosthetic device, powered via transdermal inductive transmission, carrying 1500 independent microphotodiode-amplifier-electrode elements on a 9 mm² chip, was subretinally implanted in nine blind patients. Light perception (8/9), light localization (7/9), motion detection (5/9, angular speed up to 35 deg s⁻¹), grating acuity measurement (6/9, up to 3.3 cycles per degree) and visual acuity measurement with Landolt C-rings (2/9) up to Snellen visual acuity of 20/546 (corresponding to decimal 0.037 or corresponding to 1.43 logMAR (minimum angle of resolution)) were restored via the subretinal implant. Additionally, the identification, localization and discrimination of objects improved significantly (n = 8; p < 0.05 for each subtest) in repeated tests over a nine-month period. Three subjects were able to read letters spontaneously and one subject was able to read letters after training in an alternative-force choice test. Five subjects reported implant-mediated visual perceptions in daily life within a field of 15° of visual angle. Control tests were performed each time with the implant''s power source switched off. These data show that subretinal implants can restore visual functions that are useful for daily life.     

Climatic signals in tree-ring widths and wood structure of Pinus halepensis in contrasted environmental conditions

Tree-ring widths (RW), earlywood (EW) and latewood (LW) widths, the transition from early to latewood (T) and the occurrence of intra-annual density fluctuations in EW (E-ring) and in LW (L-ring), as well as the presence of resin canals in EW and LW, were analyzed in Aleppo pine (Pinus halepensis Mill.) from three sites in Spain and one in Slovenia to find out if the anatomical characteristics can provide additional seasonal climate–growth information from contrasted environmental conditions. Principal component analysis was applied to elucidate the relationship between the measured parameters and climate. Principal component factor PC1 proved to be related to parameters of EW and the climatic variables of winter-spring; PC2 to parameters of LW and climatic variables of summer–autumn; PC3 to conditions during transitions from humid to dry periods. The three PCs vary between sites and are determined by the climatic conditions during their formation. The study demonstrates that wood anatomical features may provide complementary information to that contained in tree-ring widths. Since such results are obtained on contrasting sites, it is likely that it may be generalized over the wide range of P. halepensis distribution representing a useful proxy for studies on a regional scale.     

Transformation of Trichothecenes in Ileal Digesta and Faeces from Pigs

The capacity of pig gastrointestinal microflora to metabolise the trichothecenes 3-acetyl-deoxynivalenol (3-acDON) and nivalenol (NIV) was investigated. 3-acDON was deacetylated to DON in anaerobic incubations with pig faeces collected at different pig farms. Furthermore, both 3-acDON and NIV were metabolised to the corresponding de-epoxy metabolite in these incubates. Five pigs, in which the gastrointestinal microflora lacked the ability to transform 3-acDON and NIV to their corresponding de-epoxidated metabolites, were given low levels of DON in the feed for seven weeks. The gastrointestinal micro-organisms did not acquire the de-epoxidation ability during the seven week long exposure period. At the end of the exposure period, faeces from pigs with a known de-epoxidation ability was spread out in the pens and left for 24 hours. One week after the faeces had been spread out in the pens, the de-epoxidation ability was found in faecal incubations from four out of five experimental pigs. This change in metabolic ability of the intestinal de-epoxidation ability was not accompanied by any detectable changes in the DNA-profiles of the bacterial community composition. The results show that the intestinal de-epoxidation ability is common at pig farms in the Uppsala area, and that the ability may be transferred between pigs in a stock.     

Variance Heterogeneity in Saccharomyces cerevisiae Expression Data: Trans-Regulation and Epistasis

Here, we describe the results from the first variance heterogeneity Genome Wide Association Study (VGWAS) on yeast expression data. Using this forward genetics approach, we show that the genetic regulation of gene-expression in the budding yeast, Saccharomyces cerevisiae, includes mechanisms that can lead to variance heterogeneity in the expression between genotypes. Additionally, we performed a mean effect association study (GWAS). Comparing the mean and variance heterogeneity analyses, we find that the mean expression level is under genetic regulation from a larger absolute number of loci but that a higher proportion of the variance controlling loci were trans-regulated. Both mean and variance regulating loci cluster in regulatory hotspots that affect a large number of phenotypes; a single variance-controlling locus, mapping close to DIA2, was found to be involved in more than 10% of the significant associations. It has been suggested in the literature that variance-heterogeneity between the genotypes might be due to genetic interactions. We therefore screened the multi-locus genotype-phenotype maps for several traits where multiple associations were found, for indications of epistasis. Several examples of two and three locus genetic interactions were found to involve variance-controlling loci, with reports from the literature corroborating the functional connections between the loci. By using a new analytical approach to re-analyze a powerful existing dataset, we are thus able to both provide novel insights to the genetic mechanisms involved in the regulation of gene-expression in budding yeast and experimentally validate epistasis as an important mechanism underlying genetic variance-heterogeneity between genotypes.     

A Combination of CD28 (rs1980422) and IRF5 (rs10488631) Polymorphisms Is Associated with Seropositivity in Rheumatoid Arthritis: A Case Control Study

IntroductionThe aim of the study was to analyse genetic architecture of RA by utilizing multiparametric statistical methods such as linear discriminant analysis (LDA) and redundancy analysis (RDA).MethodsA total of 1393 volunteers, 499 patients with RA and 894 healthy controls were included in the study. The presence of shared epitope (SE) in HLA-DRB1 and 11 SNPs (PTPN22 C/T (rs2476601), STAT4 G/T (rs7574865), CTLA4 A/G (rs3087243), TRAF1/C5 A/G (rs3761847), IRF5 T/C (rs10488631), TNFAIP3 C/T (rs5029937), AFF3 A/T (rs11676922), PADI4 C/T (rs2240340), CD28 T/C (rs1980422), CSK G/A (rs34933034) and FCGR3A A/C (rs396991), rheumatoid factor (RF), anti–citrullinated protein antibodies (ACPA) and clinical status was analysed using the LDA and RDA.ResultsHLA-DRB1, PTPN22, STAT4, IRF5 and PADI4 significantly discriminated between RA patients and healthy controls in LDA. The correlation between RA diagnosis and the explanatory variables in the model was 0.328 (Trace = 0.107; F = 13.715; P = 0.0002). The risk variants of IRF5 and CD28 genes were found to be common determinants for seropositivity in RDA, while positivity of RF alone was associated with the CTLA4 risk variant in heterozygous form. The correlation between serologic status and genetic determinants on the 1st ordinal axis was 0.468, and 0.145 on the 2nd one (Trace = 0.179; F = 6.135; P = 0.001). The risk alleles in AFF3 gene together with the presence of ACPA were associated with higher clinical severity of RA.ConclusionsThe association among multiple risk variants related to T cell receptor signalling with seropositivity may play an important role in distinct clinical phenotypes of RA. Our study demonstrates that multiparametric analyses represent a powerful tool for investigation of mutual relationships of potential risk factors in complex diseases such as RA.     

Stunted at 10 Years. Linear Growth Trajectories and Stunting from Birth to Pre-Adolescence in a Rural Bangladeshi Cohort

Background

Few studies in low-income settings analyse linear growth trajectories from foetal life to pre-adolescence. The aim of this study is to describe linear growth and stunting from birth to 10 years in rural Bangladesh and to analyse whether maternal and environmental determinants at conception are associated with linear growth throughout childhood and stunting at 10 years.

Methods and Findings

Pregnant women participating in the MINIMat trial were identified in early pregnancy and a birth cohort (n = 1054) was followed with 19 growth measurements from birth to 10 years. Analyses of baseline predictors and mean height-for-age Z-scores (HAZ) over time were modelled using GLMM. Logistic regression analysis was used to investigate the associations between baseline predictors and stunting (HAZ<-2) at 10 years. HAZ decreased to 2 years, followed by an increase up to 10 years, while the average height-for-age difference in cm (HAD) to the WHO reference median continued to increase up to 10 years. Prevalence of stunting was highest at 2 years (50%) decreasing to 29% at 10 years. Maternal height, maternal educational level and season of conception were all independent predictors of HAZ from birth to pre-adolescence (p<0.001) and stunting at 10 years. The highest probability to be stunted at 10 years was for children born by short mothers (<147.5 cm) (OR_adj 2.93, 95% CI: 2.06–4.20), mothers with no education (OR_adj 1.74, 95% CI 1.17–2.81) or those conceived in the pre-monsoon season (OR_adj 1.94, 95% CI 1.37–2.77).

Conclusions

Height growth trajectories and prevalence of stunting in pre-adolescence showed strong intergenerational associations, social differentials, and environmental influence from foetal life. Targeting women before and during pregnancy is needed for the prevention of impaired child growth.     

Modulation of Cav3.2 T-type calcium channel permeability by asparagine-linked glycosylation

Low-voltage-gated T-type calcium channels are expressed throughout the nervous system where they play an essential role in shaping neuronal excitability. Defects in T-type channel expression have been linked to various neuronal disorders including neuropathic pain and epilepsy. Currently, little is known about the cellular mechanisms controlling the expression and function of T-type channels. Asparagine-linked glycosylation has recently emerged as an essential signaling pathway by which the cellular environment can control expression of T-type channels. However, the role of N-glycans in the conducting function of T-type channels remains elusive. In the present study, we used human Ca_v3.2 glycosylation-deficient channels to assess the role of N-glycosylation on the gating of the channel. Patch-clamp recordings of gating currents revealed that N-glycans attached to hCa_v3.2 channels have a minimal effect on the functioning of the channel voltage-sensor. In contrast, N-glycosylation on specific asparagine residues may have an essential role in the conducting function of the channel by enhancing the channel permeability and / or the pore opening of the channel. Our data suggest that modulation of N-linked glycosylation of hCa_v3.2 channels may play an important physiological role, and could also support the alteration of T-type currents observed in disease states.     

An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) as a potential industrial biocatalyst

The use of penicillin G acylase (PGA) covalently linked to insoluble carrier is expected to produce major advances in pharmaceutical processing industry and the enzyme stability enhancement is still a significant challenge. The objective of this study was to improve catalytic performance of the covalently immobilized PGA on a potential industrial carrier, macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) [poly(GMA‐co‐EGDMA)], by optimizing the copolymerization process and the enzyme attachment procedure. This synthetic copolymer could be a very promising alternative for the development of low‐cost, easy‐to‐prepare, and stable biocatalyst compared to expensive commercially available epoxy carriers such as Eupergit or Sepabeads. The PGA immobilized on poly(GMA‐co‐EGDMA) in the shape of microbeads obtained by suspension copolymerization appeared to have higher activity yield compared to copolymerization in a cast. Optimal conditions for the immobilization of PGA on poly(GMA‐co‐EGDMA) microbeads were 1 mg/mL of PGA in 0.75 mol/L phosphate buffer pH 6.0 at 25°C for 24 h, leading to the active biocatalyst with the specific activity of 252.7 U/g dry beads. Chemical amination of the immobilized PGA could contribute to the enhanced stability of the biocatalyst by inducing secondary interactions between the enzyme and the carrier, ensuring multipoint attachment. The best balance between the activity yield (51.5%), enzyme loading (25.6 mg/g), and stability (stabilization factor 22.2) was achieved for the partially modified PGA. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:43–53, 2016     

Using neutron crystallography to elucidate the basis of selective inhibition of carbonic anhydrase by saccharin and a derivative

Up-regulation of carbonic anhydrase IX (CA IX) expression is an indicator of metastasis and associated with poor cancer patient prognosis. CA IX has emerged as a cancer drug target but development of isoform-specific inhibitors is challenging due to other highly conserved CA isoforms. In this study, a CA IX_mimic construct was used (CA II with seven point mutations introduced, to mimic CA IX active site) while maintaining CA II solubility that make it amenable to crystallography. The structures of CA IX_mimic unbound and in complex with saccharin (SAC) and a saccharin-glucose conjugate (SGC) were determined using joint X-ray and neutron protein crystallography. Previously, SAC and SGC have been shown to display CA isoform inhibitor selectivity in assays and X-ray crystal structures failed to reveal the basis of this selectivity. Joint X-ray and neutron crystallographic studies have shown active site residues, solvent, and H-bonding re-organization upon SAC and SGC binding. These observations highlighted the importance of residues 67 (Asn in CA II, Gln in CA IX) and 130 (Asp in CA II, Arg in CA IX) in selective CA inhibitor targeting.