Onset of Chirality in Plasmonic Meta-Molecules and Dielectric Coupling.

Chirality is a fundamental feature in all domains of nature, ranging from particle physics over electromagnetism to chemistry and biology. Chiral objects lack a mirror plane and inversion symmetry and therefore cannot be spatially aligned with their mirrored counterpart, their enantiomer. Both natural molecules and artificial chiral nanostructures can be characterized by their light-matter interaction, which is reflected in circular dichroism (CD). Using DNA origami, we assemble model meta-molecules from multiple plasmonic nanoparticles, representing meta-atoms accurately positioned in space. This allows us to reconstruct piece by piece the impact of varying macromolecular geometries on their surrounding optical near fields. Next to the emergence of CD signatures in the instance that we architect a third dimension, we design and implement sign-flipping signals through addition or removal of single particles in the artificial molecules. Our data and theoretical modeling reveal the hitherto unrecognized phenomenon of chiral plasmonic-dielectric coupling, explaining the intricate electromagnetic interactions within hybrid DNA-based plasmonic nanostructures.

Effect of a direct-fed microbial (10-G Armor) on feedlot performance, carcass characteristics, and prevalence of Salmonella in fed-beef heifers.

Crossbred beef heifers (N = 1,394; initial shrunk body weight [BW] 291 ±â€…9.9 kg) were used to investigate the efficacy of 10-G Armor (Life Products, Inc., Norfolk, NE; 10-G) upon feedlot performance, carcass characteristics, and fecal and subiliac lymph nodes Salmonella prevalence. Heifers were blocked by day of arrival and allocated to 1 of 20 pens (N = 70 heifers/pen) and assigned one of two treatments (10 pens/treatment): no direct-fed microbial (CON) or 2 g/heifer/d of Lactobacillus acidophilus, Enterococcus faecium, Pediococcus pentosaceus, Lactobacillus brevis and Lactobacillus plantarum, respectively (Life Products, Inc., Norfolk, NE; 10-G). Twenty-four animals were randomly selected from each pen for Salmonella sampling. Recto-anal mucosal swab samples (RAMS) were obtained at initial processing and harvest; subiliac lymph nodes were collected at harvest. In addition, pen surface fecal pats were collected and composited by pen (10 pats per composite, 5 composites per pen) on days 0, 52, 120, and 192. Data were analyzed as a generalized complete block design, and pen served as the experimental unit. No differences were observed in live growth performance metrics (P ≥ 0.55). Yield grade distributions did not differ between treatments (P ≥ 0.62); however, cattle fed 10-G tended (P = 0.06; 14.6% vs. 18.9%) to have fewer USDA Select carcasses and more (P = 0.09; 73.6% vs. 78.0%) USDA Choice carcasses. Cattle fed 10-G tended (P = 0.10; 9.2% vs. 12.3%) to have fewer liver abscesses and had fewer (P = 0.04; 5.3% vs. 8.5%) severe liver abscesses. Salmonella prevalence of RAMS did not differ between treatments at initial processing (P = 0.97; CON = 11.6%, 10-G = 11.5%) or at harvest (P = 0.91; CON = 99.0%, 10-G = 98.6%); however, RAMS differed (P < 0.01) in Salmonella prevalence between the two collection times. Cattle fed 10-G had a lower frequency of Salmonella positive lymph nodes (P = 0.01; CON = 15.8%, 10-G = 7.4%) than CON. However, Salmonella log (mpn/g) of lymph nodes did not differ between treatments at harvest (P = 0.34; CON = 0.73, 10-G = 0.34). These data indicate that cattle fed 10-G have decreased rates of severe liver abscesses without altering live animal performance or carcass characteristics. Supplementation of 10-G significantly reduced the prevalence rate of Salmonella recovered from the subiliac lymph nodes. The factors responsible for the observed difference in the effects of 10-G on Salmonella warrant further investigation.

Chiral Photomelting of DNA-Nanocrystal Assemblies Utilizing Plasmonic Photoheating.

Chiral plasmonic nanostructures exhibit anomalously strong chiroptical signals and offer the possibility to realize asymmetric photophysical and photochemical processes controlled by circularly polarized light. Here, we use a chiral DNA-assembled nanorod pair as a model system for chiral plasmonic photomelting. We show that both the enantiomeric excess and consequent circular dichroism can be controlled with chiral light. The nonlinear chiroptical response of our plasmonic system results from the chiral photothermal effect leading to selective melting of the DNA linker strands. Our study describes both the single-complex and collective heating regimes, which should be treated with different models. The chiral asymmetry factors of the calculated photothermal and photomelting effects exceed the values typical for the chiral molecular photochemistry at least 10-fold. Our proposed mechanism can be used to develop chiral photoresponsive systems controllable with circularly polarized light.

Long- and short-ranged chiral interactions in DNA-assembled plasmonic chains.

Circular dichroism (CD) has long been used to trace chiral molecular states and changes of protein configurations. In recent years, chiral plasmonic nanostructures have shown potential for applications ranging from pathogen sensing to novel optical materials. The plasmonic coupling of the individual elements of such metallic structures is a crucial prerequisite to obtain sizeable CD signals. We here identify and implement various coupling entities-chiral and achiral-to demonstrate chiral transfer over distances close to 100 nm. The coupling is realized by an achiral nanosphere situated between a pair of gold nanorods that are arranged far apart but in a chiral fashion using DNA origami. The transmitter particle causes a strong enhancement of the CD response, the emergence of an additional chiral feature at the resonance frequency of the nanosphere, and a redshift of the longitudinal plasmonic resonance frequency of the nanorods. Matching numerical simulations elucidate the intricate chiral optical fields in complex architectures.

DNA Origami Nano-Sheets and Nano-Rods Alter the Orientational Order in a Lyotropic Chromonic Liquid Crystal.

Rod-like and sheet-like nano-particles made of desoxyribonucleic acid (DNA) fabricated by the DNA origami method (base sequence-controlled self-organized folding of DNA) are dispersed in a lyotropic chromonic liquid crystal made of an aqueous solution of disodium cromoglycate. The respective liquid crystalline nanodispersions are doped with a dichroic fluorescent dye and their orientational order parameter is studied by means of polarized fluorescence spectroscopy. The presence of the nano-particles is found to slightly reduce the orientational order parameter of the nematic mesophase. Nano-rods with a large length/width ratio tend to preserve the orientational order, while more compact stiff nano-rods and especially nano-sheets reduce the order parameter to a larger extent. In spite of the difference between the sizes of the DNA nano-particles and the rod-like columnar aggregates forming the liquid crystal, a similarity between the shapes of the former and the latter seems to be better compatible with the orientational order of the liquid crystal.

Alignment and Graphene-Assisted Decoration of Lyotropic Chromonic Liquid Crystals Containing DNA Origami Nanostructures.

Composites of DNA origami nanostructures dispersed in a lyotropic chromonic liquid crystal are studied by polarizing optical microscopy. The homogeneous aqueous dispersions can be uniformly aligned by confinement between two glass substrates, either parallel to the substrates owing to uniaxial rubbing or perpendicular to the substrates using ozonized graphene layers. These opportunities of uniform alignment may pave the way for tailored anisometric plasmonic DNA nanostructures to photonic materials. In addition, a decorated texture with nonuniform orientation is observed on substrates coated with pristine graphene. When the water is allowed to evaporate slowly, microscopic crystal needles appear, which are aligned along the local orientation of the director. This decoration method can be used for studying the local orientational order and the defects in chromonic liquid crystals.

Multi-system disorder syndromes associated with cystinuria type I.

Cystinuria type I is an autosomal recessive disorder with an exclusively renal phenotype caused by inactivating mutations in SLC3A1. Recently 3 similar but distinct syndromes associated with cystinuria type I have been described: 2p21 deletion syndrome, Hypotonia-Cystinuria Syndrome (HCS) and atypical HCS. Genetic analysis indicated that these are recessive contiguous gene deletion syndromes which differ in the number of genes affected. Patients with HCS are missing both alleles of SLC3A1 and PREPL. In atypical HCS an additional gene (C2orf34) is deleted, and finally, in the 2p21 deletion syndrome the open reading frame of PPM1B is also disrupted. With the exception of SLC3A1, the gene products have not been fully characterized. The severity of the different syndromes reflects the number of genes which are deleted. HCS, a relatively mild syndrome, is characterised by cystinuria type I, generalised hypotonia at birth, growth retardation and minor facial dysmorphic features. On the other end of the spectrum is the 2p21 deletion syndrome, a severe syndrome with a number of additional features including a moderate to severe psychomotor retardation and a decrease in activity of the respiratory chain complexes I, III, IV and V. Finally, atypical HCS displays an intermediate phenotype comparable with classical HCS but associated with mild to moderate mental retardation and a decrease in activity of only the respiratory chain complex IV. This review will focus on the phenotypic similarities and differences observed in these syndromes. Furthermore, we speculate on the function of the gene products, based on the available data.

Autosomal-dominant microtia linked to five tandem copies of a copy-number-variable region at chromosome 4p16.

Recently, large-scale benign copy-number variations (CNVs)--encompassing over 12% of the genome and containing genes considered to be dosage tolerant for human development--were uncovered in the human population. Here we present a family with a novel autosomal-dominantly inherited syndrome characterized by microtia, eye coloboma, and imperforation of the nasolacrimal duct. This phenotype is linked to a cytogenetically visible alteration at 4pter consisting of five copies of a copy-number-variable region, encompassing a low-copy repeat (LCR)-rich sequence. We demonstrate that the approximately 750 kb amplicon occurs in exact tandem copies. This is the first example of an amplified CNV associated with a Mendelian disorder, a discovery that implies that genome screens for genetic disorders should include the analysis of so-called benign CNVs and LCRs.

Global distribution of the most prevalent deletions causing hypotonia-cystinuria syndrome.

Hypotonia-cystinuria syndrome (HCS) is a recessive disorder caused by microdeletions of SLC3A1 and PREPL on chromosome 2p21. Patients present with generalized hypotonia at birth, failure to thrive, growth retardation and cystinuria type I. While the initially described HCS families live in small regions in Belgium and France, we have now identified HCS alleles in patients and carriers from the Netherlands, Italy, Canada and United States of America. Surprisingly, among the nine deletions detected in those patients, only one novel deletion was found. Furthermore, one previously described deletion was found six times, another twice. Finally, we have investigated the frequency of both deletions using a random Belgian cohort. Given the global occurrence, HCS should be considered in the differential diagnosis of neonatal hypotonia.

Interrater reliability of 3 simplified neurologic scales applied to adults presenting to the emergency department with altered levels of consciousness.

STUDY OBJECTIVE: The Simplified Motor Score was recently found to exhibit equal test performance to the Glasgow Coma Scale (GCS) when predicting 4 clinically important trauma outcomes. The present study tests the interrater reliability of the Simplified Motor Scale, the GCS and its components, and 2 other simplified neurologic scales when applied to patients presenting to the emergency department with altered levels of consciousness from any cause. METHODS: In this prospective observational study, emergency physicians independently assigned the GCS, Simplified Motor Scale, and 2 4-point scales--AVPU (Alert, responds to Verbal stimuli, responds to Painful stimuli, Unresponsive) and ACDU (Alert, Confused, Drowsy, Unresponsive)--to qualifying adult subjects. Two physicians filled out prospective data forms within 5 minutes of each other while remaining blinded to each other's assessments. Data were pooled and analyzed for interrater reliability of all scales using simple agreement, unweighted kappa, Spearman's rho, and Kendall's tau-b. RESULTS: One hundred twenty-six subjects were enrolled, with 6 later excluded. Percentage agreements were 83% for the Simplified Motor Scale, 58% for the ACDU scale, 57% for the AVPU scale, and 42% for the Total GCS. The kappa values were 0.70 for the Simplified Motor Scale, 0.43 for ACDU, 0.41 for AVPU, and 0.32 for the Total GCS. The Simplified Motor Scale also had the highest Spearman's rho (.85) and second highest Kendall's tau-b (0.81). CONCLUSION: The Simplified Motor Scale has the best interrater reliability for the assessment of altered level of consciousness of traumatic and nontraumatic cause among the scales tested.

PREPL: a putative novel oligopeptidase propelled into the limelight.

The prolyl endopeptidase-like protein PREPL has recently attracted attention because its gene is located within two contiguous gene-deletion syndromes, the 2p21 deletion syndrome and the hypotonia-cystinuria syndrome. Deletion of the gene results in hypotonia at birth, failure to thrive and growth hormone deficiency. PREPL is highly reactive against an activity-based probe, which indicates the presence of an intact catalytic machinery. However, no substrate has been found yet. The unique carboxy-terminus of the catalytic domain might contain the key to the as yet elusive specificity.

The CAREGENE study: polymorphisms of the beta1-adrenoceptor gene and aerobic power in coronary artery disease.

AIMS: The heritability of aerobic power and of the response to physical training has been shown in healthy subjects. beta(1)-Adrenergic receptor (beta(1)AR) function affects exercise performance. This study aims to investigate whether the Ser49Gly and Gly389Arg polymorphisms of the beta(1)AR gene or their haplotypes are associated with aerobic power or its response to physical training in coronary artery disease (CAD). METHODS AND RESULTS: Nine hundred and thirty-five biologically unrelated Caucasian patients with CAD who had exercised until exhaustion during graded bicycle testing at baseline and after completion of 3 months of exercise training from 1990 to 2001 (n = 1095) were eligible for inclusion in the CAREGENE (CArdiac REhabilitation and GENetics of Exercise performance) study. Polymorphisms were detected using the invader assay (Third Wave Technologiestrade mark, Madison, Wisconsin, USA). Patients with the Gly49Gly genotype had significantly higher covariate-adjusted aerobic power at baseline than those with Ser49Ser and Ser49Gly (P < 0.05). Adjusted aerobic power at baseline was highest in the Ser49-Gly389/Gly49-Gly389 and Gly49-Arg389/Gly49-Arg389 haplotype combinations. Aerobic power increased significantly (P < 0.001) with physical training. There was no association with the effect of physical training. CONCLUSION: Ser49Gly and haplotype combinations of Ser49Gly and Gly389Arg of the beta(1)AR gene are associated with aerobic power, but not with the response to physical training in patients with CAD included in the CAREGENE study.

Deletion of PREPL, a gene encoding a putative serine oligopeptidase, in patients with hypotonia-cystinuria syndrome.

In 11 patients with a recessive congenital disorder, which we refer to as "the hypotonia-cystinuria syndrome," microdeletion of part of the SLC3A1 and PREPL genes on chromosome 2p21 was found. Patients present with generalized hypotonia at birth, nephrolithiasis, growth hormone deficiency, minor facial dysmorphism, and failure to thrive, followed by hyperphagia and rapid weight gain in late childhood. Since loss-of-function mutations in SLC3A1 are known to cause isolated cystinuria type I, and since the expression of the flanking genes, C2orf34 and PPM1B, was normal, the extended phenotype can be attributed to the deletion of PREPL. PREPL is localized in the cytosol and shows homology with prolyl endopeptidase and oligopeptidase B. Substitution of the predicted catalytic residues (Ser470, Asp556, and His601) by alanines resulted in loss of reactivity with a serine hydrolase-specific probe. In sharp contrast to prolyl oligopeptidase and oligopeptidase B, which require both aminoterminal and carboxyterminal sequences for activity, PREPL activity appears to depend only on the carboxyterminal domain. Taken together, these results suggest that PREPL is a novel oligopeptidase, with unique structural and functional characteristics, involved in hypotonia-cystinuria syndrome.

The caregene study: muscle-specific creatine kinase gene and aerobic power in coronary artery disease.

In 927 biologically unrelated Caucasian patients with coronary artery disease it was investigated whether the NcoI restriction fragment length polymorphism of the muscle-specific creatine kinase (CKMM) gene is associated with aerobic power and with the response to physical training. Physical training significantly (P<0.001) increased peak oxygen consumption in the GG, AG and AA NcoI genotypes. Covariate-adjusted peak oxygen consumption at baseline, after training and the response to training were not different across CKMM NcoI genotypes.

DHPLC analysis as a platform for molecular diagnosis of congenital disorders of glycosylation (CDG).

Since 1997, the molecular basis of six different types of Congenital Disorders of Glycosylation with a defect in the synthesis of N-glycans (CDG-I) has been identified. To assure an efficient molecular diagnosis of the six genes involved in these types, we established a denaturing high-pressure liquid chromatography (DHPLC) screening procedure. Primers were designed and conditions were optimised for the analysis of each exon of the PMM2, MPI, ALG6, ALG3, DPM1 and MPDU1 genes. Forty previously described PMM2 mutations were tested to evaluate the method. All of them could be detected. Hence, the sensitivity of the technique is virtually 100%. Screening of 17 novel cases with a tentative, clinical diagnosis of CDG-Ia identified mutations on both alleles in 14 of them, thereby confirming the diagnosis. Six of these mutations were not previously reported (G15E, G42R, Y64C, E93A, G214S and D223N). Sequencing of the complete coding sequence of PMM2 in the remaining three patients did not reveal mutations, corroborating the good performance of the DHPLC method. A similar DHPLC approach was also applied to CDG-Ib, CDG-Ic, CDG-Id, CDG-Ie and CDG-If samples. New mutations were identified in MPI (Y129C) and ALG6 (G227E). All results were confirmed by sequencing. We conclude that the DHPLC platform is a sensitive and efficient method for the rapid analysis of disease genes with a limited number of exons.

A frequent mild mutation in ALG6 may exacerbate the clinical severity of patients with congenital disorder of glycosylation Ia (CDG-Ia) caused by phosphomannomutase deficiency.

Single nucleotide polymorphisms occur throughout the human genome. A gene that causes one of the congenital disorders of glycosylation (CDG) has a mutation (911T-->C ) that changes a phenylalanine to serine at position 304 (F304S) of the alpha 1,3 glucosyl transferase. We show that this change reduces the ability of the gene product to rescue defective glycosylation of an alg6-deficient strain of Saccharomyces cerevisiae during rapid growth. This finding suggested that the mutation might affect glycosylation in humans. We therefore compared the frequency of this variant in 301 controls and in 101 CDG patients who carry known mutations in other genes involved in CDG, i.e. PMM2 (CDG-Ia; 91 patients) and MPI (CDG-Ib; 10 patients). The variant allele frequency is identical in both CDG patients (0.30) and controls (0.28). Importantly, the F304S genotype frequency in 55 CDG-Ia patients classified as mild/moderate (n = 28), or severe (n = 27) was significantly higher in severely affected patients (0.41) than in mild/moderately affected patients (0.21). Mortality (n = 9) was higher when F304S was present (n = 6). Severely affected patients with the PMM2 mutations F119L/R141H (n = 22) carry the F304S mutation more often (0.36) than mildly affected patients (0.18, n = 11) with this mutation. Clinical severity of mildly affected sibs with the same PMM2 mutations did not correlate with F304S genotype. Thus, the presence of the F304S allele may exacerbate the clinical outcome, especially in severely affected CDG patients. We speculate that this type of variant may be implicated in other multi-factorial disorders that involve N-glycosylation.